Kinetic Theory - Result Question 29
29. 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
[2013]
(a) $\frac{3}{2} N_a k_B(T_2-T_1)$
(b) $\frac{3}{4} N_a k_B(T_2-T_1)$
(c) $\frac{3}{4} N_a k_B \frac{T_2}{T_1}$
(d) $\frac{3}{8} N_a k_B(T_2-T_1)$
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Answer:
Correct Answer: 29. (d)
Solution:
- (d) From first law of thermodynamics,
$\Delta Q=\Delta U+\Delta W=\frac{3}{2} \cdot \frac{1}{4} R(T_2-T_1)+0$
$=\frac{3}{8} N_a K_B(T_2-T_1)[\because K=\frac{R}{N}]$
