Question

A galvanometer of resistance G is converted into a voltmeter of range (0 − V) by using a resistance R. Find the resistance, in terms of R and G, required to convert it into a voltmeter of range (0 − V/2).

The magnetic flux through a coil of resistance 5 Ω increases with time as : φ = (2.0 t³ + 5.0 t² + 6.0 t) mWb Find the magnitude of induced current through the coil at t = 2 s.

A rectangular coil of N turns and area of cross-section A is rotated at a steady angular speed ω in a uniform magnetic field. Obtain an expression for the emf induced in the coil at any instant of time.

Two coplanar and concentric circular loops L₁ and L₂ are placed coaxially with their centres coinciding. The radii of L₁ and L₂ are 1 cm and 100 cm respectively. Calculate the mutual inductance of the loops. (Take π² = 10)

Explain the following, giving proper reason : (a) During charging of a capacitor, displacement current exists in the capacitor. But there is no displacement current when it gets fully charged. (b) The frequency of microwaves in ovens matches with the resonant frequency of water molecules. (c) Infrared waves are also known as heat waves.