Question
A very large container consists of an ideal gas. The speed of sound in the gas is x. When the pressure of the gas is doubled while keeping the temperature constant, the speed of sound now becomes y. What is the ratio of x to y?
NDA
General Ability
General Science
2026
NDA 2026 (Phase 1)
NDA General Ability Question (2026) — Solution
Options
- A. 1
- B. 2
- C. 2
- D. 4
Answer
A. 1
Step-by-step solution
The speed of sound in an ideal gas is given by the formula v = R T M . Since the temperature T is kept constant and the gas remains the same, the values of , R, T, and M are all constant. Therefore, the speed of sound is independent of the pressure of the gas as long as the temperature is constant. Alternatively, using v = P , when the pressure P is doubled at constant temperature, the density also doubles, keeping the ratio P constant. Thus, the new speed of sound y is equal to the initial speed of sound x. The ratio x y = 1. Answer: 1
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