Mathematics in Aircraft Lightning Protection: Techniques and Materials:
Multiple Choice Questions (MCQs) with Answers
1. If an aircraft experiences a lightning strike with a peak current of 200,000 amperes and the strike
lasts for 50 microseconds, what is the total charge transferred?
a) 5 coulombs
b) 10 coulombs
c) 15 coulombs
d) 20 coulombs
Answer: b) 10 coulombs
2. A copper mesh used for lightning protection weighs 200 g/m². If an aircraft requires 50 m² of
coverage, what is the total weight of the copper mesh?
a) 8 kg
b) 10 kg
c) 12 kg
d) 14 kg
Answer: b) 10 kg
3. If the electrical resistivity of aluminum is 2.82 x 10⁻⁸ Ω·m and a lightning protection strip is 2 m
long with a cross-sectional area of 10 mm², what is its resistance?
a) 5.64 x 10⁻⁶ Ω
b) 5.64 x 10⁻⁵ Ω
c) 5.64 x 10⁻⁴ Ω
d) 5.64 x 10⁻³ Ω
Answer: b) 5.64 x 10⁻⁵ Ω
4. A lightning strike generates a magnetic field of 100,000 A/m at a distance of 1 meter from the
strike point. What is the magnetic field strength at 5 meters, assuming an inverse square
relationship?
a) 4,000 A/m
b) 5,000 A/m
c) 6,000 A/m
d) 7,000 A/m
Answer: a) 4,000 A/m
5. If the dielectric strength of air is 3 x 10⁶ V/m, what is the minimum distance between two
conductive parts to prevent arcing when exposed to a potential difference of 300,000 V?
a) 5 cm
b) 10 cm
c) 15 cm
d) 20 cm
Answer: b) 10 cm
6. A carbon fiber composite panel has a surface resistivity of 1 Ω/square. If the panel is 0.5 m x 0.5 m,
what is its total resistance when measured from one edge to the opposite edge?
a) 0.5 Ω
b) 1 Ω
c) 1.5 Ω
d) 2 Ω
Answer: b) 1 Ω
7. If a lightning protection system can dissipate 90% of the strike energy, and a typical strike has 500
MJ of energy, how much energy must the aircraft structure absorb?
a) 25 MJ
b) 50 MJ
c) 75 MJ
d) 100 MJ
Answer: b) 50 MJ
8. A lightning strike generates a temperature of 30,000°C at the attachment point. If the specific heat
capacity of aluminum is 897 J/kg·K and a 100 g piece of aluminum absorbs 10% of the heat, what is
its temperature increase?
a) 334°C
b) 434°C
c) 534°C
d) 634°C
Answer: c) 534°C
9. If the skin effect depth for copper at a lightning strike frequency of 1 MHz is 0.066 mm, what is the
effective cross-sectional area of a 2 mm thick copper strip that is 10 mm wide?
a) 0.66 mm²
b) 1.32 mm²
c) 1.98 mm²
d) 2.64 mm²
Answer: b) 1.32 mm²
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
38. A composite panel has a volume resistivity of 10⁵ Ω·cm. If it is 2 mm thick and has an area of 1
m², what is its resistance measured perpendicular to the surface?
a) 0.2 Ω
b) 2 Ω
c) 20 Ω
d) 200 Ω
Answer: b) 2 Ω
39. If the magnetic field strength around a lightning channel is 100,000 A/m at a radius of 1 cm, what
is the total current in the lightning channel?
a) 6,283 A
b) 12,566 A
c) 18,849 A
d) 25,132 A
Answer: b) 12,566 A
40. A lightning protection system uses a capacitor bank to store energy. If it needs to store 10 kJ of
energy and is charged to 20 kV, what capacitance is required?
a) 25 μF
b) 50 μF
c) 75 μF
d) 100 μF
Answer: b) 50 μF
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
10. A lightning protection system has a total capacitance of 500 pF. If it experiences a voltage change
of 1,000,000 V in 1 microsecond, what is the peak current?
a) 250 A
b) 500 A
c) 750 A
d) 1000 A
Answer: b) 500 A
11. If the probability of a lightning strike on an aircraft during a flight is 0.001, what is the probability
of at least one strike occurring in 1000 flights?
a) 0.63
b) 0.73
c) 0.83
d) 0.93
Answer: a) 0.63
12. A conductive coating has a sheet resistance of 0.1 Ω/square. If it is applied to a surface area of 20
m², what is the total resistance between opposite edges of the coated area?
a) 0.005 Ω
b) 0.01 Ω
c) 0.015 Ω
d) 0.02 Ω
Answer: a) 0.005 Ω
13. If a lightning strike induces a current of 5000 A in a wire loop with an area of 2 m² and the
magnetic field changes at a rate of 10⁸ T/s, what is the inductance of the loop?
a) 0.1 μH
b) 1 μH
c) 10 μH
d) 100 μH
Answer: b) 1 μH
14. A metal fastener has a thermal conductivity of 50 W/m·K. If it experiences a temperature
gradient of 1000 K/m during a lightning strike and has a cross-sectional area of 10 mm², what is the
rate of heat transfer through the fastener?
a) 0.5 W
b) 5 W
c) 50 W
d) 500 W
Answer: a) 0.5 W
15. If the electromagnetic shielding effectiveness of a material is 60 dB, by what factor is the incident
electromagnetic field reduced?
a) 100
b) 500
c) 1000
d) 5000
Answer: c) 1000
16. A lightning strike with a peak current of 100,000 A creates a magnetic field of 20,000 A/m at a
distance of 0.5 m. What is the magnetic flux density at this point, given the permeability of free
space is 4π x 10⁻⁷ H/m?
a) 0.0251 T
b) 0.0314 T
c) 0.0377 T
d) 0.0440 T
Answer: a) 0.0251 T
17. If the electrical conductivity of a lightning protection material is 5.8 x 10⁷ S/m, what is its
resistivity?
a) 1.72 x 10⁻⁸ Ω·m
b) 1.72 x 10⁻⁷ Ω·m
c) 1.72 x 10⁻⁶ Ω·m
d) 1.72 x 10⁻⁵ Ω·m
Answer: a) 1.72 x 10⁻⁸ Ω·m
18. A lightning protection system uses a capacitor bank with a total capacitance of 1 μF. If it needs to
store 500 J of energy, what voltage must it be charged to?
a) 500 V
b) 707 V
c) 1000 V
d) 1414 V
Answer: c) 1000 V
19. If the reflection coefficient of an electromagnetic wave at the surface of a conductive material is
0.9, what percentage of the incident energy is absorbed by the material?
a) 10%
b) 19%
c) 81%
d) 90%
Answer: b) 19%
20. A lightning strike creates a current density of 10⁶ A/m² in a conductor. If the conductor has a
cross-sectional area of 5 mm², what is the total current flowing through it?
a) 5000 A
b) 10000 A
c) 15000 A
d) 20000 A
Answer: a) 5000 A
21. If the skin depth of a material at a frequency of 1 MHz is 0.1 mm, what is its skin depth at 4 MHz?
a) 0.025 mm
b) 0.05 mm
c) 0.075 mm
d) 0.1 mm
Answer: b) 0.05 mm
22. A lightning protection system has an impedance of 50 Ω. If it experiences a voltage spike of
500,000 V, what is the peak power dissipated?
a) 2.5 MW
b) 5 MW
c) 7.5 MW
d) 10 MW
Answer: b) 5 MW
23. If the probability of a lightning strike on an aircraft is 0.0001 per hour of flight, what is the
probability of at least one strike during a 5000-hour operational life?
a) 0.39
b) 0.49
c) 0.59
d) 0.69
Answer: a) 0.39
24. A metal mesh used for lightning protection has a weight of 150 g/m². If an aircraft requires 75 m²
of coverage and the maximum allowable weight increase is 15 kg, what is the safety factor?
a) 1.11
b) 1.33
c) 1.55
d) 1.77
Answer: b) 1.33
25. If a lightning strike induces a current of 1000 A in a wire with a resistance of 0.1 Ω, what is the
power dissipated in the wire?
a) 10 kW
b) 50 kW
c) 100 kW
d) 500 kW
Answer: c) 100 kW
26. A composite panel has a surface resistivity of 10 Ω/square. If it is 2 m long and 0.5 m wide, what
is its end-to-end resistance?
a) 20 Ω
b) 30 Ω
c) 40 Ω
d) 50 Ω
Answer: c) 40 Ω
27. If the magnetic permeability of a shielding material is 5000 times that of free space, and its
thickness is 0.5 mm, what is its shielding effectiveness due to absorption at 1 MHz, given that the
conductivity is 10⁷ S/m?
a) 20.4 dB
b) 30.6 dB
c) 40.8 dB
d) 51.0 dB
Answer: c) 40.8 dB
28. A lightning protection system uses a surge protector rated at 50 kA. If a lightning strike has a peak
current of 200 kA and lasts for 50 μs, what percentage of the total charge is diverted by the surge
protector?
a) 15%
b) 20%
c) 25%
d) 30%
Answer: c) 25%
29. If the dielectric breakdown strength of a material used in aircraft radomes is 20 kV/mm, what is
the minimum thickness required to withstand a potential difference of 500 kV?
a) 20 mm
b) 25 mm
c) 30 mm
d) 35 mm
Answer: b) 25 mm
30. A lightning strike transfers 100 C of charge in 50 ms. What is the average current during this time?
a) 1000 A
b) 1500 A
c) 2000 A
d) 2500 A
Answer: c) 2000 A
31. If the electrical resistivity of a lightning protection material increases by 5% for every 100°C
increase in temperature, what will be its resistivity at 500°C if its resistivity at room temperature
(20°C) is 1.68 x 10⁻⁸ Ω·m?
a) 1.89 x 10⁻⁸ Ω·m
b) 2.10 x 10⁻⁸ Ω·m
c) 2.31 x 10⁻⁸ Ω·m
d) 2.52 x 10⁻⁸ Ω·m
Answer: b) 2.10 x 10⁻⁸ Ω·m
32. A conductive coating has a thickness of 0.1 mm and a bulk resistivity of 10⁻⁶ Ω·m. What is its
sheet resistance?
a) 0.01 Ω/square
b) 0.1 Ω/square
c) 1 Ω/square
d) 10 Ω/square
Answer: a) 0.01 Ω/square
33. If the electromagnetic shielding effectiveness of a material is 40 dB at 1 MHz and increases by 10
dB for each decade increase in frequency, what is its shielding effectiveness at 100 MHz?
a) 50 dB
b) 60 dB
c) 70 dB
d) 80 dB
Answer: b) 60 dB
34. A lightning protection system uses a grounding rod with a resistance of 5 Ω. If a lightning strike
induces a current of 40,000 A, what is the voltage developed across the grounding rod?
a) 100,000 V
b) 150,000 V
c) 200,000 V
d) 250,000 V
Answer: c) 200,000 V
35. If the skin depth of copper at 1 MHz is 0.066 mm, what is the frequency at which the skin depth
is 0.033 mm?
a) 2 MHz
b) 3 MHz
c) 4 MHz
d) 5 MHz
Answer: c) 4 MHz
36. A lightning strike generates an electric field of 500 kV/m at a distance of 10 m. Assuming an
inverse square relationship, what is the electric field strength at 5 m?
a) 1000 kV/m
b) 1500 kV/m
c) 2000 kV/m
d) 2500 kV/m
Answer: c) 2000 kV/m
37. If the thermal conductivity of a lightning protection material is 400 W/m·K and its specific heat
capacity is 385 J/kg·K, what is its thermal diffusivity if its density is 8900 kg/m³?
a) 1.17 x 10⁻⁴ m²/s
b) 1.17 x 10⁻⁵ m²/s
c) 1.17 x 10⁻⁶ m²/s
d) 1.17 x 10⁻⁷ m²/s
Answer: a) 1.17 x 10⁻⁴ m²/s
41. If the electrical conductivity of a lightning protection material decreases by 0.4% for every 1°C
increase in temperature, what will be its conductivity at 200°C if its conductivity at room
temperature (20°C) is 5.8 x 10⁷ S/m?
a) 3.48 x 10⁷ S/
