WBCHSE Class 11 Physics MCQs – Thermal Expansion

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 Expansion Of Gases Multiple Choice Questions And Answers

Question 1. Both the volume and the pressure of a definite mass of gas are observed to increase. This is possible when the temperature of the gas

  1. Remains the same
  2. Decreases
  3. Increases
  4. First decreases, then increases

Answer: 3. Increases

Question 2. The value of the specific gas constant of hydrogen is

  1. \(4.16 \times 10^7 \mathrm{erg} \cdot \mathrm{g}^{-1} \cdot \mathrm{K}^{-1}\)
  2. \(0.26 \times 10^7 \mathrm{erg} \cdot \mathrm{g}^{-1} \cdot \mathrm{K}^{-1}\)
  3. \(4.80 \times 10^7 \mathrm{erg} \cdot \mathrm{g}^{-1} \cdot \mathrm{K}^{-1}\)
  4. \(5.16 \times 10^7 \mathrm{erg} \cdot \mathrm{g}^{-1} \cdot \mathrm{K}^{-1}\)

Answer: 1. \(4.16 \times 10^7 \mathrm{erg} \cdot \mathrm{g}^{-1} \cdot \mathrm{K}^{-1}\)

Question 3. At constant pressure, if the temperature of a gas is increased then its density

  1. Remains the same
  2. Decreases
  3. Increases
  4. Increases or decreases depending on the nature of the gas

Answer: 2. Decreases

Question 4. The isothermal (temperature = constant) graph of a gas is its

  1. P-V graph
  2. p-1/V graph
  3. pV-p graph
  4. pV-V graph

Answer: 1. P-V graph

Question 5. At constant pressure the volume of a definite mass of gas changes with its temperature

  1. Non-linearly
  2. Linearly
  3. In the form of a rectangular hyperbola
  4. None of the above

Answer: 2. Linearly

Question 6. pV-p graph of an ideal gas is

  1. Parallel to p-axis
  2. Parallel to pv-axis
  3. Not parallel to any axis
  4. Rectangular hyperbolic

Answer: 1. Parallel lo p-axis

Question 7. A vessel contains 1 mol of O2 gas (specific molar mass 32) at a temperature T. Pressure of this gas is p. In another identical vessel, 1 mol of He gas (specific molar mass 4) is kept at a temperature 2T. The pressure of this gas will be

  1. p/8
  2. p
  3. 2p
  4. 8p

Answer: 3. 2p

Question 8. The unit of pV in the equation pV = RT is

  1. N · m-1
  2. J
  3. J · K-1
  4. None of these

Answer: 2. J

Question 9. Two gases having the same pressure p, volume V and temperature T are mixed with each other. If the volume and temperature of the mixture are V and T respectively, then the value of pressure will be

  1. 2p
  2. p
  3. p/2
  4. 4p

Answer: 1. 2p

Question 10. Compared to that of solids and liquids, value of the coefficient of volume expansion of gases

  1. Is same
  2. Is comparatively greater
  3. Is comparatively less

Answer: 2. Is comparatively greater

Question 11. If the coefficients of volume expansion of a solid, a liquid and a gas are γs, γl and γg respectively then

  1. For Different Solids, Liquids And Gases The Values Of γs, γl And γg Are Different
  2. For Different Solids And Liquids The Values Of γs And γl Are Different, But For All Gases The Value Of γg Is The Same
  3. For Different Solids The Values Of γs Are Different But For All Liquids The Value Of γl And For All Gases The Value Of γg Are The Same
  4. For All Solids, Liquids AndGases The Values Of γs, γl And γg Respectively AreThe Same

Answer: 2. For Different Solids And Liquids The Values Of γs And γl Are Different, But For All Gases The Value Of γg Is The Same

Question 12. Coefficients of volume expansion of solids, liquids and gases are respectively γs, γl And γg Usually

  1. \(\gamma_s<\gamma_l<\gamma_g\)
  2. \(\gamma_s>\gamma_l>\gamma_g\)
  3. \(\gamma_l<\gamma_s<\gamma_g\)
  4. \(\gamma_l>\gamma_g>\gamma_s\)

Answer: 1. \(\gamma_s<\gamma_l<\gamma_g\)

Question 13. The volume of a gas at STP is 150 cm³, At constant volume, the pressure of the gas becomes 850 mmllg at a temperature 25°C. Pressure coefficient of that gas is

  1. 4.73 x 10-3 °C-1
  2. 5.73 x 10-3 °C-1
  3. 6.73 x10-3 °C-1
  4. 1 °C-1

Answer: 1. 4.73 x 10-3 °C-1

Question 14. While determining the volume coefficient of a gas, the initial volume is taken as its volume at

  1. 273°C
  2. 0°C
  3. 100°C
  4. 27°C

Answer: 2. 0°C

Question 15. Volume coefficient and pressure coefficient are equal in case of

  1. Ideal gas
  2. Real gas
  3. Hydrogen
  4. Inert gases

Answer: 1. Ideal gas

Question 16. An ideal gas is expanding such that pT² = constant. The coefficient of volume expansion of the gas is

  1. \(\frac{1}{T}\)
  2. \(\frac{2}{T}\)
  3. \(\frac{3}{T}\)
  4. \(\frac{4}{T}\)

Answer: 3. \(\frac{3}{T}\)

Question 17. Two identical containers A and B with frictionless pistons contain the same ideal gas at the same temperature and of volume. The mass of the gas in A is mA and that same in B is mB. The gas in each cylinder is now allowed to expand isothermally to the same final volume 2 V. The change in the pressure in A and B are found to be Δp and 1.5 Δp respectively. Then

  1. 4mA = 9mB
  2. 2mA = 3mB
  3. 3mA = 2mB
  4. 9mA = 4mB

Answer: 3. 3mA = 2mB

Question 18. With respect to the three quantities—pressure p, density d and absolute temperature T—the gas equation can be written as

  1. \(\frac{p_1}{T_1 d_1}=\frac{p_2}{T_2 d_2}\)
  2. \(\frac{p_1 T_1}{d_1}=\frac{p_2 T_2}{d_2}\)
  3. \(\frac{p_1 d_1}{T_2}=\frac{p_2 d_2}{T_1}\)
  4. \(\frac{p_1 d_1}{T_1}=\frac{p_2 d_2}{T_2}\)

Answer: 1. \(\frac{p_1}{T_1 d_1}=\frac{p_2}{T_2 d_2}\)

Question 19. At a pressure p, volume V and temperature T, the equation of state for 5 g of oxygen will be [R = molar gas constant]

  1. \(p V=\frac{5}{32} R T\)
  2. \(p V=5 R T\)
  3. \(p V=\frac{5}{2} R T\)
  4. \(p V=\frac{5}{16} R T\)

Answer: 1. \(p V=\frac{5}{32} R T\)

Question 20. When an air bubble rises from the bottom of a lake to the surface, its radius is doubled. Atmospheric pressure is equal to the pressure of a water column of height H. Depth of the lake is

  1. H
  2. 2H
  3. 7H
  4. 8H

Answer: 3. 7H

In this type of questions more than one options are correct.

Question 21. In the thermal expansion of an ideal gas

  1. There is no change in the temperature of the gas
  2. There is no change in the internal energy of the gas
  3. The work done by the gas is equal to the heat supplied to the gas
  4. The work done by the gas is equal to the change in its internal energy

Answer:

  1. There is no change in the temperature of the gas
  2. There is no change in the internal energy of the gas
  3. The work done by the gas is equal to the heat supplied to the gas

Question 22. From the following statements concerning ideal gas at any given temperature T, select the correct one(s).

  1. The coefficient of volume expansion at constant pressure is the same for all ideal gases
  2. The coefficient of pressure expansion at constant volume is the same for all ideal gases
  3. The coefficient of pressure expansion and volume expansion are not equal for any ideal gas
  4. The coefficient of pressure expansion and volume expansion are equal for all ideal gases

Answer:

1. The coefficient of volume expansion at constant pressure is the same for all ideal gases

2. The coefficient of pressure expansion at constant volume is the same for all ideal gases

4. The coefficient of pressure expansion and volume expansion are equal for all ideal gases

Question 23. Which of the following statements are true?

  1. The density of a gas is proportional to the absolute temperature at a constant pressure
  2. The density of a gas is inversely proportioned to the absolute temperature at constant pressure
  3. The density of a gas is proportional to the pressure at constant temperature
  4. The density of a gas is inversely proportional to the pressure at constant temperature

Answer:

2. The density of a gas is inversely proportioned to the absolute temperature at constant pressure

3. The density of a gas is proportional to the pressure at constant temperature

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