Air, treated as an ideal gas, is held in a cylinder under a light frictionless piston…

PHYSICS · Multi-part · Fermi University Physics · Thermal, Statistical & Complex Systems · The laws of thermodynamics · The laws of thermodynamics

Thermal Physics, Ch The first law: work, heat and internal energy

Problem

Air, treated as an ideal gas, is held in a cylinder under a light frictionless piston loaded so that the pressure stays at the constant value

p = 1.0\times10^5\,\mathrm{Pa}

. The gas is compressed slowly (quasistatically) from

V_1 = 2.5\,\mathrm{L}

V_2 = 1.0\,\mathrm{L}

, and during the compression

260\,\mathrm{J}

of heat leaves the gas through the cylinder wall. Take

\Delta U = Q + W

with

W

the work done on the gas and

Q

the heat delivered to it. ((a)) Find the work done on the gas. ((b)) Find the change in the internal energy of the gas.