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Daffodil Caternational Vaiversity. Dhaka, Bangladesh Electricity, Magnetism and Modern Physics [ Mathematical Problems 1. Magnetic flux of 1.5 x 104 Wb is produced when current of 3A flows through a coil of 600 turns. If the current reduces to zero in 0.06 s, then calculate (i) the induced electromotive force in the coil, (ii) self-inductance of the coil and (iii) energy stored in the coil. 2. If the current in the primary coil is changed from 6 A to 1 A in 0.05 s, then electromotive force 5V in induced in the secondary coil. What is the mutual inductance of the coil? 3. A steady current of 2A flow through an inductor of 10 Henry inductance. How can electromotive force of 100V be induced in the coil? 4, Self-inductance of an inductor is 10 Henry. If current decreases from 10 A to 7 A in 6.02 x 10-2second, find the induced electromotive force in the inductor. 5. The peal value on an alternating current in a circuit is 20A and its frequency is 50 Hz. Find the root mean square value of the current. How long will it take to reach the peak from the zero value? 6. If the equation of an alternating current is, I = 50 sin 628 t, then find (i) peak value (ii) frequency and (iii) root mean square value of the current. 7. Acoil has L=5 henry and resistance of 20 ohm. If a 100 volt emf is applied what energy is stored in the magnetic field after the current has built up to its . E94 maximum of { 8. In an LR circuit R = 3.5 ohm, L = 0.1 H. Find the current through the circuit and power factor if a 50 Hz voltage V = 220 volt is applied across the circuit. Ghalauddin || Pectuter in Physics Daffodil International University, Dhaka, Bangladesh Electricity, Magnetism and Modern Physics [3 
