First slide

Travelling wave

Question

Consider ten identical sources of sound all giving the same frequency but having phase angles which are random. If the average intensity of each source is I₀, the average of resultant intensity I due to all these ten sources will be

Easy

A

$I = 100 I_{0}$
B

$I = 10 I_{0}$
C

$I = I_{0}$
D

$I = \sqrt{10} I_{0}$

Solution

In case of interference of two waves resultant intensity
$I = I_{1} + I_{2} + 2 \sqrt{I_{1} I_{2}} cosφ$
If $ϕ$ varies randomly with time, so ${(cosφ)}_{av} = 0$
$\Rightarrow I = I_{1} + I_{2}$
For n identical waves, $I = I_{0} + I_{0} + . ...... = n I_{0}$
here $I = 10 I_{0}$ .

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App