Molecular Energy and Thermal Expansion – Rankers Physics

Kinetic Theory of Gases: Practice Problem & Solution

Assertion (A): Energy of molecules increase on increasing the temperature. Reason (R): All substances expand on increasing the temperature.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Kinetic Theory of Gases. Understanding the underlying formula is key to arriving at the correct answer below:

Concept: Temperature is a measure of average kinetic energy. Thermal expansion.
Formula: Average Kinetic Energy \( \propto T \).
Solution: Increasing temperature increases molecular kinetic energy. However, not all substances expand on heating (e.2.g., water between \( 0^{\circ}\text{C} \) and \( 4^{\circ}\text{C} \)). So R is false.

Leave a Reply

Your email address will not be published. Required fields are marked *

Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. The ratio of the specific heats $\frac{C_P}{C_V} = \gamma$ in terms of degrees of freedom ($n$) is given by: (2015)
2. The two ends of a rod of length $L$ and a uniform cross-sectional area $A$ are kept at two temperatures $T_1$ and $T_2$ ($T_1 > T_2$). The rate of heat transfer, $frac{dQ}{dt}$ through the rod in steady state is given by: (2009)
3. $10 text{ gm}$ of ice cubes at $0^circ text{C}$ are released in a tumbler (water equivalent $55 text{ g}$) at $40^circ text{C}$. Assuming that negligible heat is taken from the surroundings the temperature of water in the tumbler becomes nearly ($L = 80 text{ cal/g}$): (1988)
4. Initial pressure and volume of a gas are $P$ and $V$ respectively. First its volume is expanded to $4V$ by isothermal process and then again its volume makes to be $V$ by adiabatic process, then its final pressure is ($\gamma = 1.5$): (1999)
5. At 10°C the value of the density of a fixed mass of an ideal gas divided by its pressure is X. At 110°C this ratio is