A conducting square loop having edges of length2.0 cm is rotated through `180^@` about a diagonal in 0.20s. A magnetic field B exists in the region which si perpendicular to the loop in its initial position. If the average induced emf during the rotation is 20 mV, find the magnitude of the magnetic field.

Explanation

To solve the problem step by step, we will follow the principles of electromagnetic induction and the relevant formulas.

### Step 1: Identify the given values
- Length of the square loop, \( L = 2.0 \, \text{cm} = 0.02 \, \text{m} \)
- Area of the square loop, \( A = L^2 = (0.02 \, \text{m})^2 = 4 \times 10^{-4} \, \text{m}^2 \)
- Time taken for rotation, \( dt = 0.20 \, \text{s} \)
- Average induced emf, \( E = 20 \, \text{mV} = 20 \times 10^{-3} \, \text{V} \)
- The change in angle, \( \Delta \theta = 180^\circ \)
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