PYQ Bank

How one can obtain the various types of information about the physical conditions on the stellar surface using thermal ionization equation to interpret the stellar spectra.

Define the efficiency of a Carnot Engine. An engine is designed to have an efficiency of 25\% and to absorb heat at a temperature of 267^\circ\text{ C}. Find the maximum temperature at which it can exhaust heat.

A tank whose capacity is 0.1\text{ m}^3 contains helium at a pressure of 10\text{ atmospheres} and a temperature of 20^\circ\text{C}. A rubber weather balloon is inflated with this helium.

(i) When the pressure of helium in the balloon is 1\text{ atmosphere}, its temperature is -40^\circ\text{ C}. Find the volume of the balloon.

(ii) Eventually the helium in the balloon absorbs heat from the air around ii and returns to 20^\circ\text{ C}. Find the volume of the balloon at this time.

Write a short note on Debye's theory of specific heat.

Write a short note on Adiabatic demagnetisation.

Explain the evaporation of a liquid at a temperature below its boiling point on the basis of kinetic theory of matter.

What is the most probable distribution of speeds in a large number of molecules of a gas and indicate the steps for its derivation.

At what time are these voltage drops equal?

Show that the steady -state energy is stored in the magnetic field.

The introduction of the displacement current is one of the major contributions of Maxwell. Discuss.

Calculate the voltage drops across R and across L.

What is the limiting case of a metallic conductor in the above case ? Explain

For an R-L- C series resonant circuit, show that f_0 = \sqrt{f_1 f_2}, where f_0 is the resonance frequency and f_1, and f_2 are the half-power frequencies. Is this relation true for a parallel resonance circuit in which R, L and C are connected in parallel to each other? Explain.

Using Maxwell's equations, derive the electromagnetic wave equations for a conducting medium and solve it.

A series R-L circuit has a constant d.c. voltage V applied at the time t = 0 by closing a switch. Derive an expression for the current in the circuit.

Current is flowing in a single-turn circular coil of radius 0.1\text{ m} such that at a point 5\text{ mm} from the centre of the coil on the axis perpendicular to the plane of the coil the magnetic field is 0.1\text{ mT}. Find the current in the coil. Hence calculate the magnetic moment of the current carrying coil.

Find the power dissipated by R and power stored in L.

Explain in detail how one can obtain fringes with the Michelson Interferometer using incandescent lamps.

Four perfect polarizing plates are stacked so that the axis of each is turned 30 clockwise with respect to the preceding plate: the last plate is crossed with the first. How much of the intensity of an incident unpolarized light is transmitted by the stack ?

A book sits on a horizontal board that is undergoing simple harmonic motion with amplitude of 1\text{ m}. The coefficient of friction between the book and the board is \mu = 0.5. Find the frequency of the motion of the board at which the book is about to slip.