A conducting loop of radius 10 π cm is placed perpendicular to a uniform magnetic field of 0 . 5 T . The magnetic field is decreased to zero in 0 . 5 s at a steady rate. The induced emf in the circular loop at 0 . 25 s is:

Step-by-step solution

Given: B = 0 . 5   T     at   t = 0   &   B = 0 , at t = 0 . 5   s . Magnetic field will decrease linearly as given below. We can say, value of magnetic field at t = 0 . 25   will be   B = 0 . 25 . Therefore, ε ind  = Δ ϕ Δ t = Δ B A Δ t = A Δ B Δ t = π × 10 π 2 × 10 - 4 × 0 . 25 0 . 25 = 10 - 2 × 1 = 0 . 01   V = 10   mV