Question
Physics Question on Magnetism and matter
The true geographic north direction is found by using a compass needle. The magnetic meridian of the earth is along the axis of rotation of the earth.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
If both assertion and reason are false
Solution
A compass is simply a needle shaped magnet that is mounted so it can rotate freely about a vertical axis. When it is held in a horizontal plane, the north pole end of the needle point, generally, towards the geomagnetic north pole (really a south magnetic pole remember). Thus, true geographic north direction can not be found by using a compass needle. Now vertical plane passing through the magnetic axis of earth's magnet is called magnetic meridian. 