Heat and Thermodynamics 1 Question 17
17. $70 cal$ of heat are required to raise the temperature of 2 moles of an ideal diatomic gas at constant pressure from $30^{\circ} C$ to $35^{\circ} C$. The amount of heat required (in calorie) to raise the temperature of the same gas through the same range $\left(30^{\circ} C\right.$ to $35^{\circ} C$ ) at constant volume is
$(1985,2 M)$
(a) 30
(b) 50
(c) 70
(d) 90
Show Answer
Answer:
Correct Answer: 17. (b)
Solution:
- $Q _1=n C _p \Delta T, Q _2=n C _V \Delta T, \frac{Q _2}{Q _1}=\frac{C _V}{C _p}=\frac{1}{\gamma}$
$$ \text { or } \quad Q _2=\frac{Q _1}{\gamma}=\frac{70}{1.4}=50 cal $$
