Question

Calculate the change in internal energy of a gas kept in a rigid container when 100 J of heat is supplied to it.

Answer 1

Given:-

Heat supplied to the system,

ΔQ = 100 J

Using the first law of thermodynamics, we get

\[∆ U =  ∆ Q -  ∆ W\]

Since the container is rigid, initial volume of the system is equal to the final volume of the system. Thus,

\[∆V=V_f  -  V_i=0\]

∆W = P

∆V = 0

∆U = ∆Q = 100J

We see that heat supplied to the system is used up in raising the internal energy of the system.