JEE Main 2021 · 25 February · evening · Single correct · +4 / −1
Thermodynamic process is shown below on a P-V diagram for one mole of an ideal gas. If V₂ = 2V₁ then the ratio of temperature T₂/T₁ is :
- (a) √2
- (b) 1/√2
- (c) 1/2
- (d) 2
Answer and solution
Answer (a) √2
Solution
Physics sir · 3 steps
Swap P for nRT/V in the curve's equation and you get a direct rule linking T and V.
- Use the gas law. For one mole of ideal gas, P = RT/V. Put this into the process equation PV^(1/2) = constant.
RT/V V^(1/2) = constant ⇒ T/√V = constant ⇒ T ∝ √V
- Put in numbers. T₂/T₁ = √(V₂/V₁) = √(2V₁/V₁) = √2.
- So. The temperature rises by a factor of √2, which is option (a).
The idea to keep. For any process PVⁿ = constant, substitute P = nRT/V to get TVⁿ⁻¹ = constant. Then any temperature ratio follows from the volume ratio.
Answer from the NTA final answer key. Solution by PrepWiser.