Question

A quantity of heat Q is supplied to a diatomic gas which expands at constant pressure. The fraction of heat supplied, that contributes to the change in internal energy of the gas will be A) 5/7 B) 2/5 C) 1/3 D)1/4​

Answer 1

Answer:

A(5/7)

Explanation:

as the desired fraction is Cv/Cp so f is equal to 5/7

Answer 2

Given:

A quantity of heat Q is supplied to a diatomic gas which expands at constant pressure.

To find:

Fraction of heat supplied, that contributes to the change in internal energy of the gas?

Calculation:

So, the required fraction is :

$\sf \: \dfrac{\Delta U}{\Delta Q} = \dfrac{\mu C_{V}\Delta T}{\mu C_{P}\Delta T}$

$\sf \implies\: \dfrac{\Delta U}{\Delta Q} = \dfrac{ C_{V}}{ C_{P}}$

$\sf \implies\: \dfrac{\Delta U}{\Delta Q} = \dfrac{ \dfrac{f}{2} }{ \dfrac{f}{2} + 1}$

$\sf \implies\: \dfrac{\Delta U}{\Delta Q} = \dfrac{ f}{f + 2}$

• For diatomic gas, f = 5

$\sf \implies\: \dfrac{\Delta U}{\Delta Q} = \dfrac{ 5}{5 + 2}$

$\sf \implies\: \dfrac{\Delta U}{\Delta Q} = \dfrac{ 5}{7}$

So, fraction of heat used is 5/7.