A circular coil is rotating in a uniform magnetic field about a diameter with constant angular velocity. Then emf induced in the coil is maximum when

Area vector →A is perpendicular to the plane of the coil and this vector is rotating anticlockwise with constant angular velocity ω.At t = 0, →A is parallel to →Bϕ=→A.→B=ABcosθ=ABcosωt ε=-dϕdt=ABω. sinωt=ABωsinθε is maximum when θ=90o and ϕ=0