Download Magnetic forces on Charges and Conductors

Magnetic Forces on Charges and Conductors
Magnetic forces on charges
1. A proton moves perpendicularly to a magnetic field that has a magnitude of 4.20 x 10-14 T. What is
the speed of the particle if the magnitude of the magnetic force on it is 2.40x 10-14 N?
2. If an electron in an electron beam experiences a downward force of 2.0 x 10-14 N while travelling in
a magnetic field of 8.3 x 10-2 T west, what is the direction and magnitude of the electron’s
velocity?
3. A uniform 1.5 T magnetic filed points north. If an electron moves vertically downward (toward the
ground) with a speed of 2.5 x 107 m/s through the field, what force (direction and magnitude) will
act on it?
4. A duck flying due east passes over Atlanta, where the magnetic field of earth points north and has a
magnitude of 5.0 x 10-5 T. The duck has a charge of 4.0 x 10-8 C. If the magnetic force acting on
the duck is 3.0 X 10-11 N upward, what is the duck’s velocity (magnitude and direction)?
Magnetic forces on conductors
5. A 6.0 m wire carries a current of 7.0 A toward the +x direction. A magnetic force of 7.0 x 10-6 N
acts on the wire in the –y direction. Find the magnitude and direction of the magnetic field
producing the force.
6. A wire 1.0 m long experiences a magnetic force of 0.50 N due to a perpendicular uniform magnetic
field. If the wire carries a current of 10.0 A, what is the magnitude of the magnetic field?
7. The magnetic force on a straight 0.15 m segment of wire carrying a current of 4.5 A is 1.0 N. What
is the magnitude of the component of the magnetic field that is perpendicular to the wire?
8. The magnetic force acting on a wire that is perpendicular to a 1.5 T uniform magnetic field is 4.4 N.
If the current in the wire is 5.0 A, what is the length of the wire that is inside the magnetic field?
9. A thin 1.00 m long copper rod in a uniform magnetic field has a mass of 50.0 g. When the rod
carries a current of 0.245 A, it floats in the magnetic field. What is the field strength of the
magnetic field?
Answers: 1.) 3.57 x 1018 m/s; 2.) 1.5 x 106 m/s north; 3.) 6.0 x 10-12 N west; 4.) 15 m/s; 5.) 1.7 x
10-7 T in the +z direction; 6.) 0.050 T; 7.) 1.5 T 8.) 0.59 m; 9.) 2.00 T