Question

In the given arrangement, the loop is moved with constant velocity v in a uniform magnetic field b in a restricted region of width



a. the time for which the emf is induced in the circuit is

Answer 1

as we know emf will change when flux changes and flux will change when area changes. see figures, in the given problem, flux changes from situation (1) to (2) , but no flux will change from (2) to (3) finally, flux will change from (3) to (4).

now, total time taken from (1) to (4) , T₀ = (a + b)/v

no flux will change from (2) to (3) , T₁ = (b- a) /v

so, time taken to change flux , T = T₀ - T₁

= (a + b)/v - (b - a)/v = 2a/v