Question

Calculate the emf when the flux is given by 3sin t + 5cos t

(a) 3cos t – 5sin t

(b) -3cos t + 5sin t

(c) -3sin t – 5cos t

(d) 3cos t + 5sin t

The question was posed to me during an internship interview.

The doubt is from Faraday Law, EMF and Lenz Law in portion Magnetostics of Electromagnetic Theory

Answer 1

The correct answer is (b) -3cos t + 5sin t

The explanation: The electromotive force is given by Vemf = -dλ/dt. Thus Vemf = -dλ/dt = -(3cos t – 5sin t) = -3cos t + 5sin t.