Internal energy of n1 mol of hydrogen of temperature T is equal to the internal energy n2 mol of helium at temperature 2T. The ratio n1/n2 is :
Answer & explanation
Correct answer: option 3
Internal energy of n moles of an ideal gas at temperature T is given by :
\(U = \frac{f}{2} nRT\)
\(U_1 = U_2\)
\(f_1 n_1 T_1 = f_2 n_2 T_2\)
\(\frac{n_1}{n_2} = \frac{f_2 T_2}{f_1 T_1}\)
\(\frac{3*2}{5*1} = \frac{6}{5}\)
Here, f2 = degrees of freedom of He = 3
and, f1 = degrees of freedom of H2 = 5