A magnetic needle has a magnetic moment `5.8xx10^(-2)" A "m^(2)` and moment of inertia of `7.8xx10^(-6)"kg m"^(2)` , it performs 12 complete oscillations in 6.0 s. What is the magnitude of magnetic field ?

Explanation

To find the magnitude of the magnetic field \( B \) for the given magnetic needle, we can follow these steps:

### Step 1: Identify the given values
- Magnetic moment \( M = 5.8 \times 10^{-2} \, \text{A m}^2 \)
- Moment of inertia \( I = 7.8 \times 10^{-6} \, \text{kg m}^2 \)
- Total time for oscillations \( t = 6.0 \, \text{s} \)
- Number of oscillations \( n = 12 \)

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