Question

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

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

Answer 1

Answer: (A)

0.1 s

Answer 2

Given B₁ = 2 × 10^–2 T, B₂ = 0, θ = 0^o, N = 50, e = 0.1 V and A = 100 × 10^{– 4} m²

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

$0.1 = \frac{- 50 \times (0 - 2 \times 10^{- 2}) \times 10^{- 2} \times \cos 0^{o}}{t}$ ⇒ $t = 0.1s$