Physics 236 Worksheet: Chapter 30, Magnetic Field
1. Which of the following does not produce a magnetic field?
a. ferrous materials
b. charges at rest
c. moving charges
d. electric current
2. Which of the following statements best describes static magnetic and electric fields?
a. Electric fields begin and end on charges and magnetic fields form closed loops.
b. Magnetic fields begin and end on charges and electric fields form closed loops.
c. Electric fields begin and end on charges at rest and magnetic fields begin and end on moving charges.
3. The magnetic field at a distance of 1.0 cm from a wire is 0.6 T. At a distance of 2.0 cm it is
a. 1.2 T
b. 2.4 T
c. 0.30 T
d. 0.15 T
4. The magnetic field near a wire carrying current
a. is directed radially away from the wire
b. forms a loop around the wire
c. is directed parallel to the wire
5. A wire is carrying current to the north. The magnetic field directly below the wire is directed
a. up
b. down
c. to the east
d. to the west
e. to the north
f. to the south
6. The line integral of the magnetic field around a closed path is
a. proportional to the net current threading the path.
b. proportional to the net charge enclosed by the path.
c. zero.
7. The flux of the magnetic field through a closed surface is
a. proportional to the net current threading the surface.
b. proportional to the net charge enclosed by the surface.
c. zero.
8. The term displacement current refers to
a. the motion of charges in conductors.
b. the motion of charges in empty space.
c. the rate of change of electric flux.
d. the rate of change of magnetic flux.
9. Which of the following statements is false for ferromagnetic substances?
a. They can retain their magnetism after an external field has been removed.
b. They have negative magnetic susceptibility.
c. They can exhibit hysteresis.
d. They have high permeability.
Ans: 1-b, 2-a, 3-c, 4-b, 5-d, 6-a, 7-c, 8-c, 9-b