KVPY2018PhysicsThermodynamics
A thermally insulated rigid container of 1   L volume contains a diatomic ideal gas at room temperature. A small paddle installed inside the container is rotated from the outside, such that the pressure rises by 10 5   Pa . The change in internal energy is close to
Options
- Azero
- B67   J
- C150   J
- D250   J
Correct answer
D. 250   J
Step-by-step solution
Change in internal energy of n moles of an ideal gas, when temperature changes by Δ T is Δ U = n · f 2 · R · Δ T = f 2 n R Δ T = f 2 Δ p · V [ ∴ for ideal gas p V = n R T ] Here, f = 5 (gas is diatomic) Δ p = 10 5   Pa , V = 1   L = 10 - 3   m 3 So, Δ U = 5 2 × 10 5 × 10 - 3 = 250   J