The current in a solenoid of 240 turns, having a length of 12 cm and a radius of 2 cm, changes at a rate of 0.8 A s^–1. Find the emf induced in it.

Given:

Number of turns(n) = 240

Length of solenoid(l) = 12 cm = 0.12 m

Radius(r) = 2 cm = 0.02 m

Rate of change of current(di/dt) = 0.8 As^-1

Formula used:

L = μ₀n²A/l, where L = self inductance, μ₀ = magnetic permeability of vacuum n = number of turns, A = area, l = length

Now, emf , where L = self inductance, = rate of change of current

Putting the values:

= V (Ans)