Heat And Thermodynamics - Mechanics - Physics Previous Year Questions

If sink is at a temperature of \(-39\Upsilon\)C and source at 0\(^\circ\)C, then efficiency will be

A compound slab is made of two parallel plates of copper and brass of the same thickness and having thermal conductivities in the ratio 4 : 1. The free face of copper is at 0\(^\circ\)C. The temperature of the interface is 20\(^\circ\)C. What is the temperature of the free face of brass?

In mm\(^3\) of a gas is compressed at 1 atmospheric pressure and temperature 27\(^\circ\)C to 627\(^\circ\)C. What is the final pressure under adiabatic condition?

(\(\gamma\) for the gas = 1.5)

A gaseous mixture consists of 16 g of helium and 16 g of oxygen. The ratio \(C_p/C_V\) of the mixture is

Equal volumes of two gases, having their densities in the ratio of 1 : 16 exert equal pressures on the walls of two containers. The ratio of their rms velocities \(\left(\frac{c_1}{c_2}\right)\)

In an adiabatic process with the ratio of two specific heat, \(\gamma=\frac{3}{2}\), pressure is increased by \(\frac{2}{3}\)%, then decrease in the volume will be

For an ideal gas, coefficient of volume expansion is given by

The average energy associated with a monoatomic molecule is

Which of the following is not a green house gas?

The collision of the molecules of an ideal gas is taken as

Carnot cycle of an engine is given below

Total work done by the gas in one cycle is

The average kinetic energy of a molecule in air at room temperature of 20\(^\circ\)C

From the following p-V diagram, an ideal gas undergoing a change of state from A to B. Four different processes I, II, III and IV as shown in the figure may lead to same change of state.

If heat engine is filled at temperature 27\(^\circ\)C and heat of 100 k cal is taken from source at temperature 677\(^\circ\)C. Work done (in J) is

Consider a compound slab consisting of two different materials having equal lengths, thickness and thermal conductivities K and 2K respectively. The equivalent thermal conductivity of the slab is

In which mode of transmission, the heat waves travel along straight line with the speed of light?

There are two identical containers C\(_1\) and C\(_2\) containing to identical gases. Gas in C\(_1\) is reduced to half of its original volume adiabatically, while the gas in container C\(_2\) is also reduced to half of its initial volume isothermally. Find the ratio of final pressure in these containers. (\(\gamma\) be the adiabatic constant).

An ideal gas is taken through the cycle A \(\to\) B \(\to\) C \(\to\) A, as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process C \(\to\) A is,

In an adiabatic expansion of air, the volume is increased by \(6.2 \%\). The percentage change in pressure is \((\gamma=1.4)\)

If the ratio of specific heat of a gas at constant pressure to that at constant volume is \(\gamma\), the change in internal energy of a mass of a gas when the volume changes from \(\mathrm{V}\) to \(3 \mathrm{~V}\) at constant pressure is