Question

A source produces 25 crests and 25 troughs in 0.2 seconds then the frequency of the wave is

Answer 1

Given:

Time = 0.2 seconds

No of crests = 25

No of troughs = 25

To Find:

The frequency of the wave.

Calculation:

- One crest and one trough make up one wave.

- Here, the no of crests = the no of troughs = 25

⇒ The no of waves = 25

- As the frequency is the no of waves per unit time, we have:

Frequency = No of waves/Total time

⇒ ν = 25/0.2

⇒ ν = 125 Hz

- So, the frequency of the given wave is 125 Hertz.

Answer 2

Given:

Number of crests

= 25

Number of troughs

= 25

Time

= 0.2 seconds

To Find:

Frequency = ?

Solution:

As we know,

1 crust and 1 trough makes 1 wave,

Here, Number of waves will be "25".

Now,

⇒  $Frequency= \frac{Number \ of \ waves}{Total \ time}$

On substituting the values, we get

⇒                    $=\frac{25}{0.2}$

⇒                    $=125 \ Hz$

So that the frequency of the wave will be "125 Hz".