Question

the crest and trough are 20 cm apart in ripples on the surface of water calculate the time period and velocity of sound waves if 20ripples in one second

Answer 1

Solution:

Frequency = No of ripple produced in one second = 20 ripple = 20 Hz.
Distance between crest and trough = 20 cm;
Distance between crest and crest = 40 cm;

Then,
Wavelength of sound wave = 40 cm;

Time period of wavelength = 1/f = 1/20 sec;
T = 0.05 sec

Velocity = Frequency x Wavelength
Velocity = 20 x 40
Velocity = 800 m/s