Select True or False for each of the following statements regarding magnetism, a
ID: 1262658 • Letter: S
Question
Select True or False for each of the following statements regarding magnetism, and the earth's magnetic field "B."
The earth's B lines are parallel to the earth's surface at all points.
B does work on a charge only when the charge has a velocity component perpendicular to B.
For a bar magnet, the B - lines exit through the N pole and return through the S pole .
Like magnetic poles attract.
B does work on a charge only when the charge has a velocity component parallel to B.
The vector B acts only on charges at rest.
The magnitude of earth's B is about 1E-4 Tesla.
Explanation / Answer
False. The Earth;s B lines are not parallel to the Earth's surface at all the points. The Earth's B at the place near to the equator are parallel to each other.
False. B does work when the charge has a velocity component parallel to B. This is because the magntic force depends on the sine of the angle. Whne the charge moves perpendicular to the magnetic field, the magntic force equals zero. thus, no work is done.
True. The North pole of the bar magnetic points towards the South pole of the Earth ' B.
False. Like magnetic poles repel each other. Thus, the north-north poles of south-souht poles of the bar magnetic repels each other.
True. B does work when the charge has a velocity component parallel to B. This is because the magnetic force depends on the sine of the angle. Whne the charge moves parallel to the magnetic field, the magnetic force equals non-zero value. Thus, work is done.
False. Vector B acts only when the charge is at rest. Because the magnetic force depnds on the velocity of the charge.
False. The magnitude of the Earth's B is approximately 5 x 10-5 T which is of the order of 10-5and not 1 x 10-4 T.