Transcript Conceptual Questions Chap. 13

Conceptual Questions Chap. 19
1.
Can you use a compass to detect the currents in wires in the walls near
light switches in your home?
No, for two reasons. First, there are wires carrying currents in opposite
directions, so the net magnetic field is very small. Second, the current
direction is alternating at 60 Hz, so the magnetic field is oscillating at 60 Hz
also. This frequency is too fast for the compass to follow, so the effect on the
compass reading averages to zero.
2.
Can a constant magnetic field set into motion an electron at rest? Why
or why not?
No, since a charge at rest is completely unaffected by a magnetic field.
3.
Is it possible to orient a current loop in a uniform magnetic field such
that the loop will not tend to rotate? Explain.
Yes, if the magnetic field is directed perpendicular to the plane of the loop, the
forces on opposite sides of the loop will be equal in magnitude and opposite in
direction in the plane of the loop, which will not cause a net torque on the loop.
4.
A magnet attracts a piece of iron. The iron can then attract another
piece of iron. On the basis of domain alignment, explain what happens
in each piece of iron.
The magnet causes domain alignment in the iron such that the iron becomes
magnetic and is attracted to the original magnet. Now that the iron is
magnetic, it can produce an identical effect in another piece of iron.