Question

If heat is supplied to an ideal gas in an isothermal process, _____________ .

Options

• the internal energy of the gas will increase

• the gas will do positive work

• the gas will do negative work

• the said process is not possible

Answer 1

the gas will do positive work

 

Internal energy of the gas,

`U=intC_vdT`

Here, Cv is the specific heat at constant volume and dT is the change in temperature.

If  the process is isothermal, i.e. dT = 0, dU = 0.

Using the first law of thermodynamics, we get

ΔQ = ΔU + ΔW

But ΔU = 0

⇒ ΔQ = +ΔW

Here, ΔW is the positive work done by the gas.