# Heat and Thermodynamics · Physics · COMEDK

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## MCQ (Single Correct Answer)

COMEDK 2024 Evening Shift
The coefficient of volume expansion of glycerine is $$49 \times 10^{-5} \mathrm{~K}^{-1}$$. The percentage change in its density for a $$50^{\circ} \m... COMEDK 2024 Evening Shift The latent heat of vaporisation of water is$$2240 \mathrm{~J}$$. If the work done in the process of vaporisation of$$1 \mathrm{~g}$$is$$168 \mathr...
COMEDK 2024 Evening Shift
Internal energy of $$\mathrm{n}_1$$ moles of hydrogen at temperature T is equal to internal energy of $$\mathrm{m}_2$$ moles of helium at temperature ...
COMEDK 2024 Evening Shift
A cylinder of fixed capacity 44.81 contains hydrogen gas at STP. What is the amount of heat needed to raise the temperature of the gas in the cylinder...
COMEDK 2024 Morning Shift
A glass of hot water cools from $$90^{\circ} \mathrm{C}$$ to $$70^{\circ} \mathrm{C}$$ in 3 minutes when the temperature of surroundings is $$20^{\cir... COMEDK 2024 Morning Shift A cubical box of side$$1 \mathrm{~m}$$contains Boron gas at a pressure of$$100 \mathrm{~Nm}^{-2}$$. During an observation time of 1 second, an atom... COMEDK 2024 Morning Shift A one \mathrm{kg} block of ice at$$-1.5^{\circ} \mathrm{C}$$falls from a height of$$1.5 \mathrm{~km}$$and is found melting. The amount of ice me... COMEDK 2024 Morning Shift An electric bulb of volume$$300 \mathrm{~cm}^3$$was sealed off during manufacture at a pressure of$$1 \mathrm{~mm}$$of mercury at$$27{ }^{\circ} ...
COMEDK 2023 Morning Shift
The mean energy per molecule for a diatomic gas is
COMEDK 2023 Morning Shift
A gas is taken through the cycle $$A \rightarrow B \rightarrow C \rightarrow A$$, as shown in figure. What is the net work done by the gas? ...
COMEDK 2023 Morning Shift
The gases carbon monoxide $$(\mathrm{CO})$$ and nitrogen at the same temperature have kinetic energies $$E_1$$ and $$E_2$$, respectively. Then,
COMEDK 2023 Morning Shift
An ideal gas goes from state $$A$$ to state $$B$$ via three different processes as indicated in the $$p$$-$$V$$ diagram. If $$Q_1, Q_2$$ and $$Q_3$$ i...
COMEDK 2023 Morning Shift
If $$150 \mathrm{~J}$$ of heat is added to a system and the work done by the system is $$110 \mathrm{~J}$$, then change in internal energy will be...
COMEDK 2023 Morning Shift
Two slabs are of the thicknesses $$d_1$$ and $$d_2$$. Their thermal conductivities are $$K_1$$ and $$K_2$$, respectively. They are in series. The free...
COMEDK 2023 Morning Shift
A cylinder of radius $$r$$ and of thermal conductivity $$K_1$$ is surrounded by a cylindrical shell of inner radius $$r$$ and outer radius $$2 r$$ mad...
COMEDK 2023 Evening Shift
In an adiabatic expansion of air, the volume is increased by $$6.2 \%$$. The percentage change in pressure is $$(\gamma=1.4)$$
COMEDK 2023 Evening Shift
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...
COMEDK 2023 Evening Shift
The molecules of a given mass of a gas have root mean square speed of $$120 \mathrm{~m} / \mathrm{s}$$ at $$88^{\circ} \mathrm{C}$$ and 1 atmospheric ...
COMEDK 2023 Evening Shift
Two black bodies $$\mathrm{P}$$ and $$\mathrm{Q}$$ have equal surface areas and are kept at temperatures $$127^{\circ} \mathrm{C}$$ and $$27^{\circ} \... COMEDK 2022 If heat engine is filled at temperature 27$$^\circ$$C and heat of 100 k cal is taken from source at temperature 677$$^\circ$$C. Work done (in J) is... COMEDK 2022 From the following p-V diagram, an ideal gas undergoing a change of state from A to B. Four different processes I, II, III and IV as shown in the figu... COMEDK 2022 An ideal gas is taken through the cycle A$$\to$$B$$\to$$C$$\to$$A, as shown in the figure. If the net heat supplied to the gas in the cycle is 5... COMEDK 2022 The average kinetic energy of a molecule in air at room temperature of 20$$^\circ$$C COMEDK 2022 There are two identical containers C$$_1$$and C$$_2$$containing to identical gases. Gas in C$$_1$$is reduced to half of its original volume adiabat... COMEDK 2022 In which mode of transmission, the heat waves travel along straight line with the speed of light? COMEDK 2022 Consider a compound slab consisting of two different materials having equal lengths, thickness and thermal conductivities K and 2K respectively. The e... COMEDK 2021 In an adiabatic process with the ratio of two specific heat,$$\gamma=\frac{3}{2}$$, pressure is increased by$$\frac{2}{3}$$%, then decrease in the v... COMEDK 2021 For an ideal gas, coefficient of volume expansion is given by COMEDK 2021 Which of the following is not a green house gas? COMEDK 2021 The collision of the molecules of an ideal gas is taken as COMEDK 2021 The average energy associated with a monoatomic molecule is COMEDK 2021 Carnot cycle of an engine is given below Total work done by the gas in one cycle is... COMEDK 2020 A compound slab is made of two parallel plates of copper and brass of the same thickness and having thermal conductivities in the ratio 4 : 1. The fre... COMEDK 2020 In mm$$^3$$of a gas is compressed at 1 atmospheric pressure and temperature 27$$^\circ$$C to 627$$^\circ$$C. What is the final pressure under adiabat... COMEDK 2020 If sink is at a temperature of$$-39\Upsilon$$C and source at 0$$^\circ$$C, then efficiency will be COMEDK 2020 Equal volumes of two gases, having their densities in the ratio of 1 : 16 exert equal pressures on the walls of two containers. The ratio of their rms... COMEDK 2020 A gaseous mixture consists of 16 g of helium and 16 g of oxygen. The ratio$$C_p/C_V of the mixture is
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