. A thin magnetic needle vibrates in the horizontal plane with a period of 4 s
The needle is cut into two halves by a plane normal to magnetic axis of the needle. Then the period of vibration of each half needle is approximately
a. 4 s
b. 2 s
c. 8 s
d. 1 s
Answer ||| (b)
Solution ||| The moment of inertia of needle when it cuts into two halves by a plane normal to magnetic axis of the needle.