When an ideal gas in a cylinder was compressed isothermally by a piston, the work done on the gas was found to be 1.5 × 10^4 joules. During this process about

Q: When an ideal gas in a cylinder was compressed isothermally by a piston, the work done on the gas was found to be 1.5 × 104 joules. During this process about

(a) 3.6 × 103 cal of heat flowed out from the gas

(b) 3.6 × 103 cal of heat flowed into the gas

(c) 1.5 × 104 cal of heat flowed into the gas

(d) 1.5 × 104 cal of heat flowed out from the gas

Ans: (a)

Sol: In Isothermal process , ∆Q = ∆W = -1.5 × 104 J

∆Q =-1.5 × 104/4.2 = -3.6 × 103 cal

∆Q is -ve i.e. , heat is rejected by the gas .