# An aircraft is flying at Mach number $\mathrm{M}=1.5,$ where the ambient temperature is $250 \mathrm{~K}$. The stagnation temperature of gases at the entry to the nozzle is $800 \mathrm{~K}$. The nozzle is choked and always under expanded. Assume the molecular weight of the exhaust gases to be 29 , the ratio of specific heats to be 1.4 and the universal gas constant is $8314 \mathrm{~J} / \mathrm{kmol}-\mathrm{K}$. For which one of the nozzle exit Mach numbers given below is the propulsive efficiency highest? (A) 1 (B) 1.5 (C) 2 (D) 2.5

## Question ID - 156210 :- An aircraft is flying at Mach number $\mathrm{M}=1.5,$ where the ambient temperature is $250 \mathrm{~K}$. The stagnation temperature of gases at the entry to the nozzle is $800 \mathrm{~K}$. The nozzle is choked and always under expanded. Assume the molecular weight of the exhaust gases to be 29 , the ratio of specific heats to be 1.4 and the universal gas constant is $8314 \mathrm{~J} / \mathrm{kmol}-\mathrm{K}$. For which one of the nozzle exit Mach numbers given below is the propulsive efficiency highest? (A) 1 (B) 1.5 (C) 2 (D) 2.5

3537

(A) 1

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An aircraft is flying at Mach number $\mathrm{M}=1.5,$ where the ambient temperature is $250 \mathrm{~K}$. The stagnation temperature of gases at the entry to the nozzle is $800 \mathrm{~K}$. The nozzle is choked and always under expanded. Assume the molecular weight of the exhaust gases to be 29 , the ratio of specific heats to be 1.4 and the universal gas constant is $8314 \mathrm{~J} / \mathrm{kmol}-\mathrm{K}$.

For which one of the nozzle exit Mach numbers given below is the thrust highest?
(A) 1
(B) 1.5
(C) 2
(D) 2.5