Physics · 2014
JEE Main · 11 April 2014, Shift 1 · Q13
An ideal monoatomic gas is confined in a cylinder by a spring loaded piston of cross section 8.0 × 10^-3 m^2. Initially the gas is at 300 K and…
An ideal monoatomic gas is confined in a cylinder by a spring loaded piston of cross section $\displaystyle 8.0 \times 10^{-3} \mathrm{~m}^2$. Initially the gas is at $\displaystyle 300$ K and occupies a volume of $\displaystyle 2.4 \times 10^{-3} \mathrm{~m}^3$ and the spring is in its relaxed state as shown in figure. The gas is heated by a small heater until the piston moves out slowly by $\displaystyle 0.1$ m . The force constant of the spring is $\displaystyle 8000$ N/m and the atmospheric pressure is $\displaystyle 1.0 \times 10^5 \mathrm{~N} / \mathrm{m}^2$. The cylinder and the piston are thermally insulated. The piston and the spring are massless and there is no friction between the piston and the cylinder. The final temperature of the gas will be :
(Neglect the heat loss through the lead wires of the heater. The heat capacity of the heater coil is also negligible)

Official answer
(2)
$\displaystyle 800$ K
More from Thermodynamics
- The volume of an ideal gas (γ=1.5) is changed adiabatically from 5 litres to 4 litres. The ratio of initial pressure to final pressure is:2024
- The pressure P_1 and density d_1 of diatomic gas (γ=7/5) changes suddenly to P_2(>P_1) and d_2 respectively during an adiabatic process. The…2022
- A certain amount of gas of volume V at 27°C temperature and pressure 2 × 10^7 Nm^-2 expands isothermally until its volume gets doubled. Later it…2022
- The magnitude of heat exchanged by a system for the given cyclic process ABCA (as shown in figure) is (in SI unit):2025
- The pressure of a gas changes linearly with volume from A to B as shown in figure. If no heat is supplied to or extracted from the gas then change in…2023
- If one mole of an ideal gas at (P_1, V_1) is allowed to expand reversibly and isothermally (A to B) its pressure is reduced to one-half of the…2021
- A heat engine operates between a cold reservoir at temperature T_2=400 K and a hot reservoir at temperature T_1. It takes 300 J of heat from the hot…2021
- A monoatomic gas at pressure P and volume V is suddenly compressed to one eighth of its original volume. The final pressure at constant entropy will…2022
JEE Main 2014 Physics question, with the answer from NTA’s final answer key. Where our answers come from.