Question

A coil of 100 turns experiences a change in magnetic flux from 0.05 Wb to 0.01 Wb in 0.2 s. The induced emf is:

• A. 10 V
• B. 15 V
• C. 20 V
• D. 25 V

Hint:

Remember that the induced emf is directly proportional to the number of turns ($N$).
Do not forget to multiply the rate of change of flux by the number of turns.
A common error is calculating only the single-turn emf ($0.2\text{ V}$) and missing the factor of $100$.

Answer 1

The Correct Option is C

Step 1: Faraday's law.
$\varepsilon = N\Delta\Phi/\Delta t = 100\times(0.05-0.01)/0.2 = 100\times0.2$
\[ \boxed{20 \text{ V}} \]