A square loop of wire is held in a uniform 0.24 T magnetic field directed perpendicular to the plane of the loop. The length of each side of the square is decreasing at a constant rate of 5.4 cm/s. What emf is induced in the loop when the length is 14 cm?

Given that,

Magnetic field of 0.24T

B = 0.24T

Field perpendicular to plane i. e 90°

Rate of decrease of length of side of square is 5.4cm/s

dL/dt = 5.4cm/s = 0.054m/s

Since it is decreasing

Then, dL/dt = - 0.054m/s

When L is 14cm, what is the EMF induced?

L = 14cm = 0.14m

EMF is give as

ε = - dΦ/dt

Where flux is given as

Φ = BA

Where A is the area of the square

A = L²

Then, Φ = BL²

Substituting this into the EMF

ε = - dΦ/dt

ε = - d (BL²) / dt

B is constant

ε = - Bd (L²) / dt

ε = - 2BL dL/dr

ε = - 2 * 0.24 * 0.14 * - 0.054

ε = 3.63 * 10^-3 V

ε = 3.63mV