Heat and Thermodynamics · Physics · MHT CET (Biology)
MCQ (Single Correct Answer)
A Carnot engine has an efficiency of $\frac{1}{6}$. When the temperature of sink is reduced by 62 K , its efficiency is doubled. The temperature of the source is
If the r.m.s. velocity of gas is V at temperature T , then
In resistance thermometer, the resistance at $0^{\circ} \mathrm{C}$ and $100^{\circ} \mathrm{C}$ are $6.74 \Omega$ and $7.74 \Omega$ respectively. The temperature corresponding to $6.53 \Omega$ resistance is
An ideal gas in a container of volume 500 cc is at a pressure of $2 \times 10^5 \mathrm{~N} / \mathrm{m}^2$. The average kinetic energy of each molecule is $6 \times 10^{-21} \mathrm{~J}$. The number of gas molecules in the container is
In thermodynamic process, for free expansion, out of the following select the 'WRONG' statement.
The heat required to increase the temperature from 373 K to 573 K at constant volume for ideal monoatomic gas of 2 moles is ( $R=$ universal gas constant)
A gas at $800^{\circ} \mathrm{C}$ is cooled until both its pressure and volume are halved. The final temperature of the gas will be
When the r.m.s. velocity of a gas is denoted by ' V ' and temperature of the gas by T , which of the following relations is TRUE?
The average kinetic energy of a molecule of the gas is
Two spherical black bodies of radius $\mathrm{R}_1$ and $\mathrm{R}_2$ with surface temperatures $\mathrm{T}_1$ and $\mathrm{T}_2$ respectively. If $T_1=2 T_2$ and they radiate the same power then relation between $R_1$ and $R_2$ is
In an adiabatic change, the pressure and temperature of a diatomic gas are related as $\mathrm{P} \propto \mathrm{T}^{\mathrm{c}}$, where c is a constant. The value of c is (consider gas molecules are rigid)
A system is compressed adiabatically, then its temperature
A blackbody at $1227^{\circ} \mathrm{C}$ emits radiation with maximum intensity at a wavelength of $5600 $$\mathop {\rm{A}}\limits^{\rm{o}} $. If the temperature of the body is increased by $1000^{\circ} \mathrm{C}$, the maximum intensity will be at wavelength
An ideal gas of mass ' $M$ ' is in the state ' $A$ ' goes to another state B via three different processes. If $Q_1, Q_2$ and $Q_3$ denote the heat absorbed by the gas along the paths 1,2 and 3 respectively, then
An ideal gas is heated from $27^{\circ} \mathrm{C}$ to $627^{\circ} \mathrm{C}$ at constant pressure. If initial volume of gas is $4 \mathrm{~m}^3$, then the final volume of the gas will be
Pressure of the gas remaining same, the temperature at which r. m. s. speed of the gas molecules is double its value at $27^{\circ} \mathrm{C}$ is
Rate of flow of heat through a cylindrical rod is $\mathrm{H}_1$. The temperature of the ends of the rod are ' $\mathrm{T}_1$ ' and ' $\mathrm{T}_2$ '. If all the dimensions of the rod become double and the temperature difference remains the same, the rate of flow of heat becomes ' $\mathrm{H}_2$ '. Then $\mathrm{H}_2=$
For which of the following combinations of working temperatures, the efficiency of Carnot's engine is maximum?
A spherical body of radius ' $r$ ' radiates power ' $P$ ' at $T$ kelvin. If the radius $s$ halved and the temperature doubled the power radiated in the same time ' t ' will be
In thermodynamic process, which of the following statements is not true?
A monoatomic ideal gas, initially at temperature ' $\mathrm{T}_1$ '' is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature ' $\mathrm{T}_2$ ' by releasing the piston suddenly. $L_1$ and $L_2$ are the lengths of the gas columns before and after the expansion respectively. Then $\frac{T_1}{T_2}$ is
The volume of a block of metal at $30^{\circ} \mathrm{C}$ changes by $0.12 \%$ when its temperature is increased to $70^{\circ} \mathrm{C}$. The coefficient of linear expansion of the metal is
A fixed mass of gas at constant pressure occupies a volume ' $V$ '. The gas undergoes a rise in temperature so that the r.m.s. velocity of the molecule is doubled. The new volume will be