AP and TS EAMCET Engineering Model Paper 3

An air-cored solenoid is of length 0.3m, area of cross section 1.2×10−3m2 and has 2500 turns. Around its central section, a coil of 350 turns is wound. The solenoid and the coil ore electrically insulated from each other. Calculate the emf induced in the coil if the initial current of 3 A in the solenoid is reversed in 0.25 sec