Question

Magnetic flux of a 20-turn coil is reduced to zero from 0.3 weber in one second. Then the induced e.m.f between the terminals of the coil is:

• A. 1.5 V
• B. 6 V
• C. 2.5 V
• D. 3 V

Hint:

Faraday's law states that the induced e.m.f is proportional to the rate of change of magnetic flux, with the number of turns in the coil as a factor.

Answer 1

The Correct Option is B

The induced e.m.f \( \mathcal{E} \) is calculated using Faraday's law: \[\n\mathcal{E} = -N \frac{\Delta \Phi}{\Delta t}\n\] With: - \( N = 20 \) - \( \Delta \Phi = 0.3 \, \text{weber} \) - \( \Delta t = 1 \, \text{second} \) The induced e.m.f is: \[\n\mathcal{E} = -20 \times \frac{0.3}{1} = -6 \, \text{V}\n\] Therefore, the induced e.m.f is 6 V.