Question

In water tank on throwing a stone 20 full river are produced in 1 seconds the distance between the crest and throw is 10 centimetre calculate the wavelength of river Presidency of ripple velocity of ripple

Answer 1

Given values:

If stone drop in tank 20 full ripple produced in 1 sec;

We know that frequency of a wave is the number of waves produced in 1 second.

Distance between crest and though = 10 cm;
Total no of wave produced in 1 sec = 20;
So, the frequency of this wave is, f = 20 Hz

Distance between crest and though = half of the wavelength
10 cm = Half the wavelength
Wavelength = 10 x 2 = 20 cm;
Wavelength = 20 cm;

Now,

Velocity = Frequency x Wavelength
Velocity = 10 x .20
Velocity = 2.0 m/s

Answer 2

It is given that 20 ripples are formed when a stone is thrown , in 1 sec.

Hence , frequency = no: of waves formed in 1 sec.

Here ,
frequency = no: of ripples formed in 1 sec.
= 20 Hz


Wavelength is the distance between two consecutive crests or troughs.

Here we are given the half distance of wavelength.

Hence , wavelength = 2 x distance between the crest and trough
= 2 x 10
= 20 cm = 0.2 m


As we all know ,
velocity = wavelength x frequency

= 0.2 x 20
=4 m/s