Q72 / 90 · JEE Main 2022 (27 Jul Shift 2) · Physics
A compass needle of oscillation magnetometer oscillates times per minute at a place of dip . The number of oscillations per minute become at another place of dip. The ratio of the total magnetic field at the two places is:
- Correct answerA
- B
- C
- D
Solution
At point the needle oscillates times per minute. Therefore, time period and at point , .
The time period of oscillation magnetometer is given by,
And
Taking ratio,
Hence, the correct answer is option: 'A'.