# A balloon has 5.0g mole of helium at $7^{\large\circ}C$.Calculate the total internal energy of the system

$\begin{array}{1 1}(A)\;3.48\times 10^4J\\(B)\;1.74\times 10^4J\\(C)\;3.48\times 10^6J\\(D)\;3.48\times 10^5J\end{array}$

$\large\frac{3}{2}$$KT\times N=\large\frac{3}{2}$$\times 30\times 10^{23}\times 1.3\times 10^{-23}\times 280$
$\Rightarrow 1.74\times 10^4J$
Hence (B) is the correct answer.