Exams › JEE Main › Physics

Following statements are given: (A) The average kinetic energy of a gas molecule decreases when the temperature is reduced. (B) The average kinetic energy of a gas molecule increases with increase in pressure at constant temperature. (C) The average kinetic energy of a gas molecule decreases with increase in volume. (D) Pressure of gas increases with increase in temperature at constant pressure. (E) The volume of gas decreases with increase in temperature. Choose the correct answer from the options given below: (1) (A) and (D) only (2) (A), (B) and (D) only (3) (B) and (D) only (4) (A), (B) and (E) only

1. (A) and (D) only
2. (A), (B) and (D) only
3. (B) and (D) only
4. (A), (B) and (E) only

Correct answer: (A), (B) and (D) only

Solution

Statements (A), (B), and (D) are correct because the average kinetic energy of gas molecules is directly related to temperature, increasing with temperature and decreasing when temperature drops (A). Pressure and temperature are also directly related at constant volume, meaning that increasing pressure at constant temperature is not accurate, but the relationship between temperature and pressure is valid (D). Statement (B) is misleading as pressure does not increase with temperature at constant temperature, but rather at constant volume.

Related JEE Main Physics questions

• An ideal gas is enclosed in a thermally insulated sealed container. During an adiabatic expansion, the mean interval between successive molecular collisions varies with the volume $V$ as $V^q$. What is the value of $q$ in terms of $\gamma=C_p/C_v$?
• Assuming ideal gas behaviour, the ratio of the density of ammonia to that of hydrogen chloride at the same temperature and pressure is: (Atomic mass of Cl = 35.5 u) [JEE Main Online 2018]
• The value closest to the thermal velocity of a helium atom at room temperature (300 K) in m s\(^{-1}\) is
• A 15 g sample of nitrogen gas is enclosed in a vessel at a temperature of $27^\circ\text{C}$. Heat is supplied to the gas so that the rms speed of the molecules is doubled. The heat transferred is about: [Take $R=8.3\ \text{J mol}^{-1}\text{K}^{-1}$]
• For a gas at 1 atm pressure, the rms speed of the molecules is \(200\,\text{m/s}\) at \(127^\circ\text{C}\). At \(2\) atm pressure and \(227^\circ\text{C}\), the rms speed of the molecules will be:
• An HCl molecule has rotational, translational, and vibrational motions. If the rms velocity of HCl molecules in its gaseous phase is \(\bar v\), \(m\) is its mass, and \(k_B\) is Boltzmann's constant, then its temperature will be:

⚔️ Practice JEE Main Physics free + battle 1v1 →