Question

State Lenz's Law. In a closed circuit, the induced current opposes the change in magnetic flux that produced it as per the law of conservation of energy. Justify.

State Faraday's law of electromagnetic induction and mention the utility of Lenz's law. Obtain an expression for self-inductance of a coil in terms of its geometry and permeability of the medium.

A resistance of 20 Ω, a capacitance of 80 μF and an inductor of 50 mH are connected in series. This combination is connected across a 220 V ac supply of variable frequency. When the frequency of supply equals the natural frequency of the circuit, calculate : (1) angular frequency of supply (2) impedance of the circuit

A long solenoid of radius r consists of n turns per unit length. A current I = I₀ sin ωt flows in the solenoid. A coil of N turns is wound tightly around it near its centre. What is : (a) the induced emf in the coil ? (b) the mutual inductance between the solenoid and the coil ?