Heat and Thermodynamics

Heat given to a body, which raises its temperature by 1ºC is known as

A monoatomic gas \(\left(\gamma=\frac{5}{3}\right)\) initially at \(27^{\circ} \mathrm{C}\) having volume '\(\mathrm{V}\)' is suddenly compressed to one-eighth of its original volume \(\left(\frac{\mathrm{V}}{8}\right)\). After the compress...

Three discs \(\mathrm{x}, \mathrm{y}\) and \(\mathrm{z}\) having radii \(2 \mathrm{~m}, 3 \mathrm{~m}\) and \(6 \mathrm{~m}\) respectively are coated on outer surfaces. The wavelength corresponding to maximum intensity are $$300 \mathrm{~nm...

When the rms velocity of a gas is denoted by '\(v\)', which one of the following relations is true?
(\(\mathrm{T}=\) Absolute temperature of the gas.)

At what temperature does the average translational kinetic energy of a molecule in a gas becomes equal to kinetic energy of an electron accelerated from rest through potential difference of 'V' volt?
(\(\mathrm{N}=\) number of molecules, $$...

Internal energy of \(n_1\) moles of hydrogen at temperature '\(T\)' is equal to internal energy of '\(n_2\)' moles of helium at temperature \(2 T\), then the ratio \(\mathrm{n}_1: \mathrm{n}_2\) is
[Degree of freedom of \(\mathrm{He}=3\), D...

An ideal gas with pressure \(\mathrm{P}\), volume \(\mathrm{V}\) and temperature \(\mathrm{T}\) is expanded isothermally to a volume \(2 \mathrm{~V}\) and a final pressure \(\mathrm{P}_{\mathrm{i}}\). The same gas is expanded adiabatically ...

For a monoatomic gas, the work done at constant pressure is '\(\mathrm{W}\)' The heat supplied at constant volume for the same rise in temperature of the gas is \([\gamma=\frac{C_p}{C_v}=\frac{5}{2}\) for monoatomic gas]

A monoatomic ideal gas initially at temperature \(\mathrm{T}_1\) is enclosed in a cylinder fitted with 8 frictionless piston. The gas is allowed to expand adiabatically to a temperature \(\mathrm{T}_2\) by releasing the piston suddenly. $$\...

The temperature difference between two sides of an iron plate, \(1.8 \mathrm{~cm}\) thick is \(9^{\circ} \mathrm{C}\). Heat is transmitted through the plate \(10 \mathrm{k} \mathrm{cal} / \mathrm{sm}^2\) at steady state. The thermal conduct...

Which one of the following p-V diagram is correct for an isochoric process:

The molecular masses of helium and oxygen are 4 and 32 respectively. The ratio of r.m.s. speed of helium at 327\(^\circ\) to r.m.s. speed of oxygen at 27\(^\circ\) will be

A monoatomic gas is suddenly compressed to \((1 / 8)^{\text {th }}\) of its initial volume adiabatically. The ratio of the final pressure to initial pressure of the gas is \((\gamma=5 / 3)\)

A metal sphere cools at the rate of \(1.5^{\circ} \mathrm{C} / \mathrm{min}\) when its temperature is \(80^{\circ} \mathrm{C}\). At what rate will it cool when its temperature falls to \(50^{\circ} \mathrm{C}\). [Temperature of surrounding ...

Assume that for solar radiation, surface temperature of the sun is \(6000 \mathrm{~K}\). If Wien's constant 'b' is \(2.897 \times 10^{-3} \mathrm{~mK}\), the value of maximum wavelength will be

Which one of the following is NOT a correct expression for an ideal gas?
[\(\mathrm{C_p}=\) Molar specific heat of a gas at constant pressure,
\(\mathrm{C_v}=\) Molar specific heat of a gas at constant volume,
\(\mathrm{Y}=\) Ratio of two s...

Which one of the following statements is wrong for an isobaric process?

For a perfectly black body, coefficient of emission is

The temperature of a black body is increased by \(50 \%\), then the percentage increase in the rate of radiation by the body is approximated

Two rods of different metals have coefficients of linear expansion '\(\alpha_1\)' and '\(\alpha_2\)' respectvely. Their respective lengths are '\(\mathrm{L}_1\)' and '\(\mathrm{L}_2\)'. At all temperatures (\(\mathrm{L}_2-\mathrm{L}_1\)) is...

If \(\mathrm{m}\)' represents the mass of each molecules of a gas and \(\mathrm{T}\)' its absolute temperature then the root mean square speed of the gas molecule is proportional to

An ideal gas at pressure '\(p\)' is adiabatically compressed so that its density becomes twice that of the initial. If \(\gamma=\frac{c_p}{c_v}=\frac{7}{5}\), then final pressure of the gas is

The initial pressure and volume of a gas is '\(\mathrm{P}\)' and '\(\mathrm{V}\)' respectively. First by isothermal process gas is expanded to volume '\(9 \mathrm{~V}\)' and then by adiabatic process its volume is compressed to '$$\mathrm{V...

A cylindrical rod has temperatures '\(T_1\)' and '\(T_2\)' at its ends. The rate of flow of heat is '\(Q_1\)' cal \(\mathrm{s}^{-1}\). If length and radius of the rod are doubled keeping temperature constant, then the rate of flow of heat '...

For an ideal gas, \(R=\frac{2}{3} C_v\). This suggests that the gas consists of molecules, which are [\(\mathrm{R}=\) universal gas constant]

Equal volumes of two gases, having their densíties in the ratio of \(1: 16\) exert equal pressures on the walls of two containers. The ratio of their rms speads (\(\mathrm{C}_1: \mathrm{C}_2)\) is

The rms speed of a gas molecule is '\(\mathrm{V}\)' at pressure '\(\mathrm{P}\)'. If the pressure is increased by two times, then the rms speed of the gas molecule at the same temperature will be

For a gas molecule with 6 degrees of freedom, which one of the following relation between gas constant '\(\mathrm{R}\)' and molar specific heat '\(\mathrm{C}_{\mathrm{v}}\)' is correct?

A cylindrical rod is having temperatures \(\theta_1\) and \(\theta_2\) at its ends. The rate of heat flow is '\(Q\)' \(\mathrm{J}{\mathrm{s}}^{-1}\). All the linear dimensions of the rod are doubled by keeping the temperatures constant. Wha...

Let '\(\mathrm{W}_1\)' be the work done in blowing a soap bubble of radius '\(r\)' from soap solution at room temperature. The soap solution is now heated and second soap bubble of radius '\(2 r\)' is blown from the heated soap solution. If...

Which of the following statements is true?
(\(\Delta \mathrm{U}=\) increase in internal energy, \(\mathrm{dW}=\) work done by the system)

If the temperature of the sun is doubled, the rate of energy received by the earth will be increased by a factor

A polyatomic gas \((\gamma=4 / 3)\) is compressed to \(\left(\frac{1}{8}\right)^{\text {th }}\) of its volume adiabatically. If its initial pressure is \(\mathrm{P}_0\), its new pressure will be

The translational kinetic energy of the molecules of a gas at absolute temperature (T) can be doubled

If the pressure of an ideal gas is decreased by \(10 \%\) isothermally, then its volume will

The rate of flow of heat through a copper rod with temperature difference \(28^{\circ} \mathrm{C}\) is \(1400 \mathrm{~cal} \mathrm{~s}^{-1}\). The thermal resistance of copper rod will be

An ideal gas having molar mass '\(\mathrm{M}_0\)', has r.m.s. velocity 'V' at temperature 'T'. Then

An ideal gas at \(27^{\circ} \mathrm{C}\) is compressed adiabatically to \((8 / 27)\) of its original volume. If ratio of specific heats, \(\gamma=5 / 3\) then the rise in temperature of the gas is

The emissive power of sphere of area \(0.04 \mathrm{~m}^2\) is \(0.7 \mathrm{~k} \mathrm{~cal} \mathrm{~s}^{-1} \mathrm{~m}^{-2}\). The amount of heat radiated in 20 second is

The change in internal energy of the mass of a gas, when the volume changes from '\(\mathrm{V}\)' to '\(2 \mathrm{~V}\)' at constant pressure 'P' is (\(\gamma=\) Ratio of Cp to Cv)

Which one of the following equations specifies an isobaric process? \([Q=\) heat supplied \(\Delta P, \Delta V\) and \(\Delta T\) are change in pressure, volume and temperature respectively]

Find the value of \(-\)197\(^\circ\)C temperature in Kelvin.

A black reactangular surface of area '\(a\)' emits energy '\(\mathrm{E}\)' per second at \(27^{\circ} \mathrm{C}\). If length and breadth is reduced to \(\left(\frac{1}{3}\right)^{\text {rd }}\) of initial value and temperature is raised to...

A monoatomic gas at pressure '\(\mathrm{P}\)' having volume '\(\mathrm{V}\)' expands isothermally to a volume \(2 \mathrm{~V}\) and then adiabatically to a volume \(16 \mathrm{~V}\). The final pressure of the gas is $$\left(\gamma=\frac{5}{...

A black body has maximum wavelength '\(\lambda_{\mathrm{m}}\)' at temperature \(2000 \mathrm{~K}\). Its corresponding wavelength at temperature \(3000 \mathrm{~K}\) will be

The temperature difference bewtween two sides of metal plate, \(3 \mathrm{~cm}\) thick is \(15^{\circ} \mathrm{C}\). Heat is transmitted through plate at the rate of \(900 \mathrm{~kcal}\) per minute per \(\mathrm{m}^2\) at steady state. Th...

The molar specific heats of an ideal gas at constant pressure and volume are denoted by '\(\mathrm{C}_{\mathrm{p}}\)' and '\(C_v\)' respectively. If \(\gamma=\frac{C_p}{C_v}\) and '\(R\)' is universal gas constant, then \(C_v\) is equal to

Two rods of same length and material are joined end to end. They transfer heat in 8 second. When they are joined in parallel they transfer same amount of heat in same conditions in time

If '\(\mathrm{E}\)' is the kinetic energy per mole of an ideal gas and '\(\mathrm{T}\)' is the absolute temperature, then the universal gas constant is given as

In thermodynamics, for an isochoric process, which one of the following statement is INCORRECT?