11.

A Carnot engine, having an efficiency of η = 1/10 as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is

• 99 J

• 90 J

• 1 J

• 1 J

One end of a thermally insulated rod is kept at a temperature T₁ and the other at T₂. The rod is composed of two sections of lengths

• (k₂

• (k₂

• (k₁

• (k₁

If C_p and Cv denote the specific heats of nitrogen per unit mass at constant pressure and constant volume respectively, then

• C_p – C_v = R/28

• C_p −C_v = R/14

• C_p −C_v = R

• C_p −C_v = R

A charged particle moves through a magnetic field perpendicular to its direction. Then

• the momentum changes but the kinetic energy is constant

• both momentum and kinetic energy of the particle are not constant

• both, momentum and kinetic energy of the particle are constant

• both, momentum and kinetic energy of the particle are constant

Two springs, of force constants _k1 and k₂, are connected to a mass m as shown. The frequency of oscillation of the mass is f. If both k₁ and k₂ are made four times their original values, the frequency of oscillation becomes

• f/2

• f/4

• 4f

• 4f

When a system is taken from state i to state f along the path iaf, it is found that Q = 50 cal and W = 20 cal. Along the path’ ibf Q = 36 cal. W along the path ibf is

• 6 cal

• 66 cal

• 16 cal

• 16 cal

A particle of mass m executes simple harmonic motion with amplitude ‘a’ and frequency ‘ν’. The average kinetic energy during its motion from the position of equilibrium to the end is

• π²m a² v²

• ma² v²/4

• 4π²ma²v²

• 4π²ma²v²

In an a.c. circuit the voltage applied is E = E₀ sinπt. The resulting current in the circuit is I = I₀ sin .The power consumption in the circuit is given by

• 

• P = zero

• 
• 

An electric charge 10^-3 µC is placed at the origin (0,0) of X - Y coordinate system. Two points A and B are situated at  and (2, 0) respectively. The potential difference between the points A and B will be

• 9 volt

• 0 volt

• 2 volt

• 2 volt

A battery is used to charge a parallel plate capacitor till the potential difference between the plates becomes equal to the electromotive force of the battery. The ratio of the energy stored in the capacitor and the work done by the battery will be

• 1

• 2

• 1/4

• 1/4