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The pressure wave, P = 0.01 sin [1000t - 3x] N m⁻², corresponds to the sound produced by vibrating blade on a day when atmospheric temperature is 0°C. On some other day when temperature is T, the speed of sound produced by the same blade at the same frequency is found to be 336 m s⁻¹. A proximate value of T is -

1. 4°C
2. 12°C
3. 11°C
4. 15°C

Correct answer: 4°C

Solution

At 0 C, v0 = 1000/3 = 333.3 m/s. Since v is proportional to sqrt(T), T = 273*(336/333.3)^2 ≈ 277.4 K ≈ 4 C, so the answer is 4 C.

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