if the frequency of a tuning fork is 400 Hz and the velocity of sound in air is 320m/s find the distance travelled by the sound while the fork completes 20 vibrations.
Answers
v = 320m/s , n = 400 Hz
λ = v / n
= 320/400
=0.8 m
the distance travelled during which the fork makes 20 vibrations is
= 20×0.8
=16m
Concept:
Frequency is the number of vibrations that are performed by any particle of medium per second. It is expressed by the formula, n = 1/T
Given:
Frequency, n = 400 Hz
Velocity, v = 320 m/s
No. of vibrations = 20
Find:
We need to determine the distance travelled by the sound.
Solution:
To calculate the distance travelled by the sound we first need to determine the time period, t.
The time period is to be determined by the frequency since they are related to each other as n = 1/T where n = frequency and T = time period
Therefore, T = 1/n
T = 1/400 = 0.0025 seconds
Now, the total time is determined by,
Total time = time period × Number of vibrations
Total time = 0.0025 × 20
Total time = 0.05 seconds.
We know, the distance travelled by sound is the product of speed and time
Therefore, distance = speed × time
Distance = 320 × 0.05
Distance = 16 m
Thus, the distance travelled by the sound while the fork completes 20 vibrations is 16m.
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