The temperature at which the speed of sound in air becomes double of its value at 27°C?

56°C

12.3°C

927°C

None of these

Speed of sound in air is proportional to the square root of absolute temperature v ∝ √T.

To double the speed, temperature must increase 4 times in Kelvin:

At 27°C = 300 K → 4 × 300 = 1200 K → 1200 - 273 = 927°C