Isothermal Process and Adiabatic Expansion – Rankers Physics

Thermodynamics: Practice Problem & Solution

Assertion (A): If heat is supplied to an ideal gas in an isothermal process, the internal energy of the gas increases. Reason (R): When an ideal gas expands adiabatically, it does positive work and its internal energy increases.  
(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(3) (A) is true but (R) is false
(4) Both (A) and (R) are false

Short Solution (Best for NEET):

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

For an ideal gas in an isothermal process, temperature is constant, so internal energy \(Delta U = 0\). Thus (A) is false. In adiabatic expansion, work \(W > 0\) is done by the gas and heat \(Q = 0\), so \(Delta U = -W < 0\), meaning internal energy decreases. Thus (R) is false. Both (A) and (R) are 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Your email address will not be published.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. Assertion (A): When hot water is suddenly poured in cold beaker of thick glass, the beaker cracks. Reason (R): Glass is bad conductor of heat and outer surface of the beaker does not expand.
2. Assertion (A): The atoms of a monoatomic gas have less degrees of freedom as compared to molecules of the diatomic gas. Reason (R): The ratio of \(\frac{C_p}{C_v}\) for an ideal diatomic gas is more than that for an ideal monoatomic gas (where \(C_p\) and \(C_v\) have usual meaning).  
3. Assertion (A): Absolute zero temperature is not the zero energy temperature. Reason (R): At absolute zero temperature the gas may possess potential energy.  
4. When 150 gm of ice at \( 0^\circ\text{C} \) is mixed with 60 gm of water at \( 50^\circ\text{C} \) in a container, the resulting temperature is
5. Assertion (A): During the melting of a slab of ice at \(273\text{ K}\) at \(1\text{ atm}\) positive work is done on the ice-water system by the atmosphere. Reason (R): In above process, the internal energy of ice-water system increases.