An insulated cylinder of volume 60 cm³ is filled with a gas at 27°C and 2 atmospheric pressure. Then the gas is compressed making the final volume as 20 cm³ while allowing the temperature to rise to 77°C. The final pressure i s _______ atmospheric pressure.
Physics · Thermodyanmics · thermodynmic process and work done
JEE Mains 2026 22 January Evening Shift

Question

An insulated cylinder of volume 60 cm³ is filled with a gas at 27°C and 2 atmospheric pressure. Then the gas is compressed making the final volume as 20 cm³ while allowing the temperature to rise to 77°C. The final pressure i s _______ atmospheric pressure.

Physics · Thermodyanmics · thermodynmic process and work done

JEE Mains 2026 22 January Evening Shift

G1 Physics · Accepted Answer

For a fixed amount of ideal gas, P₁V₁/T₁ = P₂V₂/T₂. Convert temperatures to kelvin: T₁ = 27 + 273 = 300 K. T₂ = 77 + 273 = 350 K. Given, P₁ = 2 atm, V₁ = 60 cm³, V₂ = 20 cm³. Therefore, P₂ = P₁V₁T₂/(T₁V₂) = (2×60×350)/(300×20) = 7 atm. Hence the answer is 7.