A coil with an average diameter of 0.02 m is placed perpendicular to a magnetic field of 6000 T. If the induced e.m.f. is 11 V when magnetic field is changed to 1000 T in 4 s, what is the number of turns in the coil ?

Explanation

To solve the problem, we need to find the number of turns (n) in a coil given the change in magnetic field, the induced electromotive force (e.m.f.), and the area of the coil. Let's break it down step by step.

### Step 1: Identify the given values
- Diameter of the coil (d) = 0.02 m
- Radius of the coil (r) = d/2 = 0.02 m / 2 = 0.01 m
- Initial magnetic field (B_initial) = 6000 T
- Final magnetic field (B_final) = 1000 T
- Induced e.m.f. (E) = 11 V
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