Electromagnetic Induction

Around the central part of an air cored solenoid of length \(20 \mathrm{~cm}\) and area of cross section \(1.4 \times 10^{-3} \mathrm{~m}^2\) and 3000 turns, another coil of 250 turns is closely wound. A current \(2 \mathrm{~A}\) in the solenoid is reversed in \(0.2 \mathrm{~s}\), then the induced emf produced is