Transcript lec20

A bar magnet is spinning clockwise as viewed
from a position south of the magnet, about a
horizontal, north-south axis that is perpendicular
to, and passes through the center of, the bar
magnet. What is the direction of the electric
field, if any, directly above the magnet at an
instant when the magnet is vertical with its north
end up?
a) Northward
b) Southward
c) Eastward
d) Westward
e) Upward
f) Downward
g) There is no electric field.
h) None of the above.
A tiny lead pellet having a negative charge is
falling toward the ground. In the rest frame of
the ground, at a point due north of the pellet at
the same elevation as the pellet, what is the
direction of the magnetic field, if any, due to the
falling particle?
a) Northward
b) Southward
c) Eastward
d) Westward
e) Upward
f) Downward
g) There is no magnetic field.
h) None of the above.
A horizontal loop carries a current that is
clockwise as viewed from above, but, the loop is
rotating counterclockwise as viewed from above.
What is the direction of the electric field, if any,
due to the rotating loop at a point at the same
elevation as, and due north of, the loop?
a) Northward
b) Southward
c) Eastward
d) Westward
e) Upward
f) Downward
g) There is no electric field.
h) None of the above.
A positively charged particle is moving
northward, directly toward point P. In the
reference frame in which point P is at rest, what
is the direction of the magnetic field, if any, at
point P?
a) Northward
b) Southward
c) Eastward
d) Westward
e) Upward
f) Downward
g) There is no magnetic field.
h) None of the above.
In your reference frame, a downward-directed
magnetic field vector is moving eastward at the
speed of light. In your reference frame, what is
the direction of the corresponding electric field, if
any?
a) Northward
b) Southward
c) Eastward
d) Westward
e) Upward
f) Downward
g) There is no electric field.
h) None of the above.
In your reference frame, a northward-directed
electric field vector is moving downward. In your
reference frame, what is the direction of the
corresponding magnetic field, if any?
a) Northward
b) Southward
c) Eastward
d) Westward
e) Upward
f) Downward
g) There is no magnetic field.
h) None of the above.