Question

A tuning fork of frequency 420 Hz completes 70 vibrations. Find the distance travelled by sound in air (v = 360 m $s^{-1})$

• A. 20 m
• B. 50 m
• C. 60 m
• D. 80 m

Answer 1

Answer: (C)

60 m

Number of vibration in $1sec=420$

Time taken for $70$ vibrations $=\frac{70}{420}=0.167s$

Distance=speed$\times$ Time

As, speed of sound = $360m/s$

$\Rightarrow 360\times 0.167=60m$

Sound travels $60m$ when the turning fork makes $70$ vibration.