Frequency: 1 Mark
Wavelength: 2 Marks
Velocity: 2 Marks
(a) Frequency. We know that frequency of a wave is the number of waves produced in 1 second
Here, No. of waves produced in 3 seconds = 1500
So, No. of waves produced in 1 second =15003
= 500
So, the frequency of this sound wave is 500 hertz.
(b) Wavelength. In a sound wave, the distance covered by a compression and an adjacent rarefaction is equal to its wavelength. This distance has been given to be 68 cm. So, the wavelength (λ) of this sound wave is 68 cm.
(c) Velocity. The formula for calculating the velocity of a sound wave is:
v=f×λ
Here, Frequency, f = 500 Hz (Calculated above)
And, Wavelength, λ=68 cm (Calculated above)
=68100 m
= 0.68 m
Putting, these values of f and λ in the above formula, we get:
v=500×0.68
= 340 m/s
Thus, the velocity (or speed) of the sound waves is 340 m/s.