Question

A magnetic field of 2 × 10^{– 2} T acts at right angles to a coil of area 100 cm² with 50 turns. The average emf induced in the coil is 0.1 V, when it is removed from the field in time t. The value of t is

• A. 0.1 sec
• B. 0.01 sec
• C. 1 sec
• D. 20 sec

Answer 1

Answer: (A)

0.1 sec

Answer 2

$e = - \frac{N(B_{2} - B_{1})A\cos\theta}{\Delta t}$

$\Rightarrow 0.1 = \frac{- 50 \times (0 - 2 \times 10^{- 2}) \times 100 \times 10^{- 4} \times \cos 0^{o}}{t}$

$\Rightarrow t = 0.1sec$.