Question

The amount of heat energy required to raise the temperature of 1 g of Helium at NTP, from $T_1 K$ to $T_2 K$ is :

• A. $ \frac{3}{4} N_a k_B \left( \frac{T_2}{T_1} \right)$
• B. $ \frac{3}{8} N_a k_B \left( T_2 - T_1 \right)$
• C. $ \frac{3}{2} N_a k_B \left( T_2 - T_1 \right)$
• D. $ \frac{3}{4} N_a k_B \left( T_2 - T_1 \right)$

Answer 1

Answer: (B)

Number of moles in$1g\,\, He = \frac{1}{4}$
Amount of heat energy required to raise its temepratre from $T_1K\,\, to\,\, T_2K$
$ = nC_v \Delta T$
$= \left(\frac {1}{4}\right) \left(\frac {3}{2} R\right) (T_2 - T_1)$
$= \frac {3}{8} k_BN_A(T_2 - T_1)$