TERRESTRIAL MAGNETISM

Question 1

1. The red pole of a freely suspended magnet will point towards ……. and at latitude 60°N will point ……. at an angle known as the angle of …….

Answer 1

d. the north magnetic pole, downwards, dip.

Question 2

2. If the total force of the earth’s field at a point is T and the horizontal and vertical components H and Z, the value of H is found by the formula:

Answer 2

c. H = T cos dip

Question 3

3. The directive force of the earth’s magnetic field:

Answer 3

d. is greatest at the magnetic equator.

Question 4

4. The slow change in the earth’s magnetic variation is known as the ……. change and is caused by …….

Answer 4

c. secular, westerly movement of the magnetic pole.

Question 5

5. Soft iron is comparatively ……. to magnetise whilst hard iron is ……. to demagnetise.

Answer 5

a. easy; difficult.

Question 6

6. Which of the following materials are classed as ferromagnetic:

Answer 6

d. iron, cobalt steel, chromium steel.

Question 7

7. The magnetic moment of a magnet:

Answer 7

a. is the product of pole strength and effective length.