lab7
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Lab7_phy2_report.docxTA: Keslo Estil SEC#: Name:
Lab 7. Magnetic Force on Moving Charges
Objectives
· Investigate the magnetic force on the current in a conductor and what it depends on.
· Understand the right-hand rule, or bottle cap rule.
Preliminary Questions (1,2)
Analysis (1-5)
Note: Show all equations, calculations and very clear screenshots for the graphs with fits to receive full credit.
Data Tables
|
Current (A) |
Mass (kg) |
Force (N) |
Current (A) |
Mass (kg) |
Force (N) |
|
0.0 |
|
|
3.0 |
|
|
|
0.5 |
|
|
3.5 |
|
|
|
1.0 |
|
|
4.0 |
|
|
|
1.5 |
|
|
4.5 |
|
|
|
2.0 |
|
|
5.0 |
|
|
|
2.5 |
|
|
|
|
|
Mass with I = 0 … (kg)
|
Length (cm) |
Mass (kg) |
Force (N) |
|
1.2 |
|
|
|
2.2 |
|
|
|
3.2 |
|
|
|
4.2 |
|
|
|
6.4 |
|
|
|
8.4 |
|
|
|
Number of magnets |
Mass With I = 0 (kg) |
Mass With I = 2A (kg) |
Force (N) |
|
1 |
|
|
|
|
2 |
|
|
|
|
3 |
|
|
|
|
4 |
|
|
|
|
5 |
|
|
|
|
6 |
|
|
|
41
Lab 7. Magnetic Force on Moving Charges
Whereas an electric field E exerts a force qE on a charge q placed in the field, a magnetic field, B only exerts a force on a charge if the charge is moving. The force is given by F qv B= . An alternative expression applies when the moving charges constitute a current I in a straight length
of a conductor: F I B= where is in the direction of I . This relationship will be explored through the use of a "current balance." You may have learned the "right-hand rule" for a cross product to give you the direction of F . Instead, you can use the "bottle cap rule." (Point your arm in the direction of the first vector, then rotate your arm towards the direction of the second vector. Imagine applying that rotation to a bottle cap. The direction in which the bottle cap advances, i.e. tightens down or loosens up, gives the correct direction.) OBJECTIVES
Investigate the magnetic force on the current in a conductor and what it depends on. Understand the right-hand rule, or bottle cap rule.
MATERIALS Current balance apparatus connecting wires Power supply or battery Labquest Mini computer
meter stick high current probe
PRELIMINARY QUESTIONS 1. If you want to maximize the magnetic force on a current in a conductor, how should you
orient the current relative to the magnetic field? 2. If you want the force to be zero, in what two directions could you orient the current relative
to the magnetic field? PRELIMINARY SETUP
Figure 1
41
Lab 7. Magnetic Force on Moving
Charges
Whereas an electric field
E
exerts a force
qE
on a charge q placed in the field, a magnetic field,
B only exerts a force on a charge if the charge is moving. The force is given byFqvB=. An
alternative expression applies when the moving charges constitute a current I in a straight length
of a conductor:
FIB=
where is in the direction of I . This relationship will be explored
through the use of a "current balance." You may have learned the "right-hand rule" for a cross
product to give you the direction of
F
. Instead, you can use the "bottle cap rule." (Point your arm
in the direction of the first vector, then rotate your arm towards the direction of the second
vector. Imagine applying that rotation to a bottle cap. The direction in which the bottle cap
advances, i.e. tightens down or loosens up, gives the correct direction.)
OBJECTIVES
Investigate the magnetic force on the current in a conductor and what it depends on.
Understand the right-hand rule, or bottle cap rule.
MATERIALS
Current balance apparatus connecting wires
Power supply or battery
Labquest Mini
computer
meter stick
high current probe
PRELIMINARY QUESTIONS
1. If you want to maximize the magnetic force on a current in a conductor, how should you
orient the current relative to the magnetic field?
2. If you want the force to be zero, in what two directions could you orient the current relative
to the magnetic field?
PRELIMINARY SETUP
Figure 1
