Most Important Selected Qs for JEE AdvancedPhysicsThermodynamics
An ideal monoatomic gas undergoes a process in which P=3 V^3 . Choose the correct statements.
Options
- AIf volume increases then temperature will also increase
- BIf temperature of the gas decreases, then pressure must also decrease.
- CFor expansion, heat will have to be supplied to the gas.
- DIf temperature increases then work done by gas is positive.
Correct answer
D. If temperature increases then work done by gas is positive.
Step-by-step solution
P=V^3 , for ideal gas PV = nRT (A) relation between V and T V (3 V^3 )=n R T V ^4= ( nR 3 ) T V ^4 T (B) Relation between P and T aligned & PV = nRT P ( P 3 )^ 1 / 3 = nRT & P ^ 4 / 3 T aligned (C) For expansion V increases work-done : positive internal energy : increases Hence, heat will have to supplied to the gas. (D) As T V ^4 with increase in temperature, volume increases Hence work done is positive.