2025 Exam Questions
Q. Find kinetic energy of 1 litre of an ideal gas at S.T.P.
Q. Calculate the energy radiated in one minute by a perfectly black body of surface area 200 \mathrm{~cm}^{2} when it is maintained at 127^{\circ} \mathrm{C} .
Q. State and prove Kirchhoff’s law of heat radiation.
iii. Which of the following materials belongs to diathermanous substance?
(A) wood
(B) iron
(C) glass
(D) copper
2024 Exam Questions
Q. Draw a neat labelled diagram of Ferry’s perfectly black body.
Q. Compare the rms speed of hydrogen molecules at 2270C with rms speed of oxygen molecule at 127 OC. Given that molecular masses of hydrogen and oxygen are 2 and 32 respectively.
2023 Exam Questions
Q. If ‘n’ is the number of molecules per unit volume and ‘d’ is the diameter of the molecules, the mean free path ‘λ’ of molecules is
(A) \sqrt{\frac2{\pi\;nd}}
(B) \frac1{2\;{\pi nd}^2}
(C) \frac1{\sqrt2\;{\pi nd}^2}
(D) \frac1{\sqrt{2\pi nd}}
Q. On the basis of kinetic theory of gases obtain an expression for pressure exerted by gas molecules enclosed in a container on its walls.
Q. Compare the rate of loss of heat from a metal sphere at 827oC with rate of loss of heat from the same at 427oC, if the temperature of surrounding is 27oC.
2022 Exam Questions
Q. The root mean square speed of the molecules of a gas is proportional to_____.
(A) \sqrt T
(B) \frac1{\sqrt T}
(C) T
(D) 1/T
Q. The average K.E. of a gas is _____.
(A) directly proportional to absolute temperature of gas
(B) directly proportional to square of absolute temperature of gas
(C) directly proportional to square root of absolute temperature of gas
(D) inversely proportional to absolute temperature of gas
Q. Derive an expression for a pressure exerted by a gas on the basis of kinetic theory of gases.
Q. What is perfectly black body?
Q.Define
i) Emissive power
ii) Co-efficient of emission
Q. The difference between the two molar specific heats of a gas is 9000 J/kg K. If the ratio of the two specific heats is 1.5, calculate the two molar specific heats.
Q. Calculate the energy radiated in half a minute by a black body of surface area 200 cm2 at 127oC.
