Question

A small piece of wire is passed through the gap between the poles of a magnet in 0.1 sec. An emf of 4 × 10⁻⁸ V is induced in the wire, the magnetic flux between the poles is 

(a) 10 Wb 

(b) 0.1 Wb 

(c) 4 × 10⁻⁹ Wb

(d) 4 × 10⁻² Wb

Answer 1

Correct option (c) 4 × 10⁻⁹ Wb

Explanation:

Here : e = 4 × 10⁻⁸ volt, dt = 0.1 sec 

Putting the values of e and dt in eq. (1), we get

dϕ  = 4 × 10⁻⁸ × 0.1 = 4 × 10⁻⁹ Wb