1. The problem statement, all variables and given/known data A uniform magnetic field B is perpendicular to the plane of a circular wire loop of radius R. The magnitude of the field varies with time according to B=B0exp(-t/τ) where B0 and τ are constants. The time dependence of the induced emf in the loop is a) exp(-t2/τ2) b) 1+exp(-t2/τ2) c) 1-exp(-t/τ) d) -exp(-t/τ) 2. Relevant equations emf=-dΘ/dt Θ=∫B.dA 3. The attempt at a solution εdt=-dΘ ∫εdt=-∫dΘ ∫εdt=-Θ ∫εdt=-∫B.dA ∫εdt=-B∏R2 ∫εdt=-B0.exp(-t/τ)∏R2 So with this I guessed that the time dependence would be option d) -exp(-t/τ) Is this the correct answer?