Question

A circular coil carrying a current of 2.5 A is free to rotate about an axis in its plane perpendicular to an external magnetic field. When the coil is made to oscillate, the time period of oscillation is \( T \). If the current through the coil is 10 A, the time period of oscillation is.

• A. \( T/2 \)
• B. \( T \)
• C. \( 2T \)
• D. \( T/4 \) \bigskip

Hint:

The time period of oscillation for a current-carrying coil is inversely proportional to the current.

Answer 1

The Correct Option is A

Step 1: The time period of oscillation of a current-carrying coil is inversely proportional to the current: \[ T \propto \frac{1}{I} \] If the current increases by a factor of 4 (from 2.5 A to 10 A), the time period will decrease by a factor of 2. Therefore, the new time period will be \( \boxed{T/2} \). \bigskip