The speed of sound in air is about 331 m s-1 at 0 °C and nearly 344 m s-1 at 22 °C. Class 9

The speed of sound in air is about 331 m s^-1 at 0 °C and nearly 344 m s^-1 at 22 °C. Class 9

Question 1.

The speed of sound in air is about 331 m s^-1 at 0 °C and nearly 344 m s^-1 at 22 °C. Roughly how much extra time will the sound of thunder take to travel a distance of 1720 m, if the air temperature changes from 22 °C to 0 °C? Assume that all other conditions remain unchanged. Class 9

Answer:

Time at 22°C = distance / speed = 1720 / 344 = 5 s

Time at 0°C = distance / speed = 1720 / 331 ≈ 5.196 s

Extra time = 5.196 - 5 = ≈ 0.196 s ≈ 0.2 s

Question 2.

The variation of density of medium for a sound wave propagating with a speed of 340 m s^-1 is shown in Fig. Calculate the wavelength and frequency of the sound wave. Class 9

Answer:

Wavelength λ = 8 cm = 0.08 m

Frequency v = v/λ = 340 / 0.08 = 4250 Hz