Chapter 20, Problem 1RQ

Review Question 20.1 What aspects of compass behavior near a magnet give us information about the direction of magnetic influence, and what aspects give us information about the strength?

To determine

The aspects of compass behavior near a magnet, which give us information about magnetic influence and strength.

Answer to Problem 1RQ

Solution:

The needle of a compass gets deflected towards the magnet instead of showing the actual direction of the Earth’s north and south poles. The stronger the magnetic influence, the larger is the deflection from the ideal position.

Explanation of Solution

Introduction:

A compass works on the magnetic principle that the needle of the compass shows the direction of the North pole as the Earth’s core is considered a big magnet.

Explanation:

The Earth contains molten metals inside it, which at a large scale is considered a big bar magnet with its north and south poles associated with the Earth’s north and south poles.

The compass itself contains a small magnet, whose north pole gets aligned towards Earth’s north pole when no other magnetic field is present. Whenever a new magnetic field is introduced near the compass, it gets deflected towards this new magnetic field as the magnet at the Earth’s core is situated at larger distance. Thus, even a small magnetic influence succeeds to change the position of the needle of the compass.

Also, the magnetic force between two bodies is directly proportional to the strength of the magnetic poles of the bodies. Hence, stronger the magnetic influence, the greater will be the deflection of the needle from the north pole of the compass.

Conclusion:

The compass will get deflected towards the magnet even when there is a small magnetic influence.