Question

A rigid storage tank of 2.5 $m^3$ contains 3 kg argon at 28${}^{\circ }C$, heat is then transferred to the argon from a furnace maintained at 1200${}^{\circ }C$ untill the specific entropy of the argon gas is increased by 0.343 kJ/kgK. what is the percentage increase in absolute temperature of argon gas during the process? Take $C_v=0.312kJ/kgK,R=0.20kJ/kgK$ for argon gas

• A. 50%
• B. 100%
• C. 200%
• D. 400%

Answer 1

The correct option is C 200%

Since the storage is rigid
V=C
During heat addition
for process 1-2

$s_2=s_1+0.343$
also $s_2-s_1=c_v\text{ln}\left(\frac{T_2}{T_1}\right)$

$\Rightarrow 0.343=c_v\text{ln}\left(\frac{T_2}{T_1}\right)$

$0.343=0.312\text{ln}\left(\frac{T_2}{T_1}\right)$

$\Rightarrow \frac{T_2}{T_1}=e^{\left(\frac{0.343}{0.312}\right)}$

$=e^{\left(1.09936\right)}$

$=3.0$

$(\frac{T_2}{T_1}-1)\times 100=(3-1)\times 100$

$\Rightarrow \frac{T_2-T_1}{T_1}\text{\%}=200\text{\%}$