Magnetic Force Homework
Name: _____________________________ Class: __________
1. If a positively charged particle moves to the left in a magnetic field that points up, which way will the
force act?
2. A wire carries a current as shown below subjected to a magnetic field. Which way does it feel a
force?
3. An electron feels a force down while it is moving out of the paper. Which way does the magnetic
field point?
4. A positive charge moving towards west is deflected towards north. What is the direction of the
magnetic field?
5. Which of the following statements are always true?
a. Fmis always perpendicular to v.
b. v is always perpendicular to B.
c. Fm is always perpendicular to B.
6.
A uniform magnetic field B, with magnitude B = 1.2 x 10-3 T, points vertically upward
throughout the volume of a laboratory chamber. A proton with a velocity v = 3.2 x 107 m/s
enters the laboratory moving horizontally from south to north. Find (a) the magnitude and
(b) the direction of magnetic force on the proton.
7. The magnetic field above has magnitude 3.0 T. For each of the following particles placed in
the field, find (a) the force exerted by the magnetic field on the particle, and (b) the acceleration
of the particle. Be sure to give magnitude and direction in each case.
a) an e- at rest
b) an e- moving ↑ at 2 m/s
c) an e- moving ← at 2 m/s
d) a proton moving
at 2 m/s
e) an e- moving up and to the right, at an angle of 30° to the horizontal, at 2 m/s
f) an e- moving up and to the left, at an angle of 30° to the horizontal, at 2 m/s
g) a proton moving ⊗ at 2 m/s
8. An electron moves north at a velocity of 9.8  104 m/s and has a magnetic force of 5.6  10–18 N
exerted on it. If the magnetic field points upward, what is the magnitude of the magnetic field?
9. An electron moves north at a velocity of 2.7  104 m/s and has a magnetic force of 9.5  10–18 N
exerted on it. If the magnetic field points upward, what is the magnitude of the magnetic field?