A diatomic gas (γ = 1.4) does 100 J of work when it is expanded isobarically. Then the heat given to the gas ____ J.
Q. A diatomic gas (\( \gamma = 1.4 \)) does 100 J of work when it is expanded isobarically. Then the heat given to the gas ____ J.
Correct Answer: 350

Explanation (Complete Step-by-Step)

For an isobaric process:

\[ W = P\Delta V = nR\Delta T \]

Heat supplied in isobaric process is:

\[ Q = nC_p \Delta T \]

Now,

\[ \gamma = \frac{C_p}{C_v} \]

Also,

\[ C_p - C_v = R \]

From \( \gamma = 1.4 \):

\[ C_p = \frac{\gamma R}{\gamma - 1} \]

\[ C_p = \frac{1.4R}{0.4} \]

\[ C_p = 3.5R \]

Now,

\[ W = nR\Delta T = 100 \]

\[ Q = nC_p \Delta T \]

\[ Q = n(3.5R)\Delta T \]

\[ Q = 3.5(nR\Delta T) \]

\[ Q = 3.5W \]

\[ Q = 3.5 \times 100 \]

\[ Q = 350 \text{ J} \]

Therefore, heat given to the gas = 350 J

Related JEE Main Questions

Important for Competitive Exams

jee mains jee advanced iit jee neet physics thermodynamics isobaric process heat and work gamma relation physics mcq jee mains physics revision iit jee preparation neet preparation physics engineering entrance exam physics conceptual questions competitive exam physics numerical physics jee physics practice questions exam oriented preparation gas laws thermodynamics problems jee mains preparation jee advanced preparation iit entrance exam neet exam physics

Updated for JEE Main 2026: This PYQ is important for JEE Mains, JEE Advanced and other competitive exams. Practice more questions from this chapter.

Scroll to Top