High School Grade 12 Physics Question

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PHYSICS 30 Atomic Nucleus Exam WR

Name: _______________ Date: ________________

Written Response #1

Use the following information to answer the next question.

• Determine the velocity of neutron after the decay. (3 marks)

The sun produces energy through nuclear fusion. In one particular reaction, energy is released when a hydrogen – 2 nucleus fuses with a hydrogen – 3 nucleus. This produces a helium – 5 nucleus that is unstable and that decays to helium 4 nucleus and a neutron. The fusion reaction chain is

HenHeHH 42 1 0

5 2

3 1

2 1 +→→+

The masses of two of these particles are given in the table below.

Particle Isotope Notation Mass (10-27 kg) Helium – 4 He42 6.648 84

Neutron n10 1.674 93 The decay of helium – 5 to helium – 4 and a neutron forms an isolated system. In this system, the energy equivalence of the mass defect is observed as an increase in the system’s kinetic energy. A helium – 5 nucleus, at rest, decay. Both the neutron and the helium – 4 nucleus move away from the location of the decay. The helium – 4 nucleus has a momentum of 1.903 06 × 10-20 Ns and a kinetic energy of 2.723 50 × 10-14 J.

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Name: ___________________ • Determine the mass of the helium-5 nucleus. (5 marks)

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Written Response #2 Name: _________________

Use the following information to answer the next questions.

• On the grid below, graph the data with the manipulated variable on the horizontal axis. Provide a suitable title for your graph. (3 marks)

While studying the radioactive phosphorus isotope isotope P3415 , it was discovered that a 128 g sample had decayed to 4.48 g after 60 s. The following table provides data corresponding to the decay. Mass (g) 128.0 73.0 41.9 23.9 13.7 7.80 4.48 Time (s) 0.00 10.0 20.0 30.0 40.0 50.0 60.0

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Name: __________________ • Using your graph, or some other appropriate method, determine the half-life of phosphorus-34. Indicate how you determined your answer. (1 mark) • When phosphorus-34 decays, it emits a particle. An experiment similar to the J.J. Thomson experiment is performed to determine the charge-to-mass ratio of this particle. It is found that the particle moves undeflected through mutually perpendicular magnetic and electric fields of 2.00 × 10-3 T and 1.08 × 104 N/C, respectively. When the electric field is turned off, the particle is found to deflect to a radius of 1.53 × 10-2m. Using the formula on the data sheets, determine the type of particle emitted. Show all the steps needed to make this determination. (4 marks)

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Name: _________________ • Using your periodic table, write the complete equation for the decay you just found, identifying the product isotope. If you were not able to get an answer for the previous bullet, assume an alpha decay. (2 marks) • How would a gamma ray have been affected by passing through a magnetic field as mentioned in the third bullet? (1 mark)