Question

A coil having area 2m² is placed in a magnetic field which  changes from 1wb/m² to 4wb/m² in an interval of 2 second. The emf induced in the coil of single turn is....

(a) 4v 

(b) 3v 

(c) 1.5v 

(d) 2v

Answer 1

The correct option  (b) 3v 

Explanation:

emf induced in coil of single turn = e = – (dɸ/dt)

= – (d/dt) (A × B) ---- ɸ = A × B

= – A(dB/dt)

∴ e = – 2 × [{4 – 1}/2] = – 3v  

i.e  |e| = 3v.