Consider ten identical sources of sound all giving the same frequ… - Vidyadip

MCQ

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 $I_0$, the average of resultant intensity $l$ due to all these ten sources will be

A
$I=100 I_0$
✓
$I=10 I_0$
C
$ I=I_0$
D
$I=\sqrt{10} I_0$

✓

Answer

Correct option: B.

$I=10 I_0$

In case of interference of two waves resultant intensity $I=I_1+I_2+2 \sqrt{I_1 I_2}\cos\phi$
If $\phi$ varies randomly with time, so $(\cos \phi)_{a v}=0$ $\Rightarrow I=I_1+I_2$
For $n$ identical waves, $I=I_0+I_0+\ldots \ldots =n I_0$ here $I=10I_0$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "MCQ" from Waves and Sound→Waves and Sound — all question types→JEE physics STD 12 Science question papers→CBSE Board STD 12 Science question papers→CBSE Board question paper generator→

Similar questions

The internal resistances of two cells shown are $0.1 \Omega$ and $0.3 \Omega$. If $R=0.2 \Omega$, the potential difference across the cell

The force required to separate two glass plates of area $10^{-2} \mathrm{~m}^2$ with a film of water $0.05 \mathrm{~mm}$ thick between them, is (Surface tension of water is $70 \times 10^{-3} \mathrm{~N} / \mathrm{m}$ )

A metal rod of length $2 \mathrm{~m}$ is rotating with an angular velocity of $100\ \mathrm{rad} / \mathrm{sec}$ in a plane perpendicular to a uniform magnetic field of $0.3$ $T$. The potential difference between the ends of the rod is

In supplying 400 calories of heat to a system, the work done will be

The resistance of a wire of uniform diameter $d$ and length $L$ is $R$. The resistance of another wire of the same material but diameter $2 d$ and length $4 L$ will be

When a tuning fork $A$ of unknown frequency is sounded with another tuning fork $B$ of frequency $256 \mathrm{~Hz}$, then $3$ beats per second are observed. After that $A$ is loaded with wax and sounded, the again $3$ beats per second are observed. The frequency of the tuning fork $A$ is

Two cars are moving on two perpendicular roads towards a crossing with uniform speeds of $72 \mathrm{~km} / \mathrm{hr}$ and $36 \mathrm{~km} / \mathrm{hr}$. If first car blows horn of frequency $280 \mathrm{~Hz}$, then the frequency of horn heard by the driver of second car when line joining the cars make $45^{\circ}$ angle with the roads; will be

Two cars $A$ and $B$ at rest at same point initially. If $A$ starts with uniform velocity of $40 m / sec$ and $B$ starts in the same direction with constant acceleration of $4 m / s ^2$, then $B$ will catch $A$ after how much time

The coordinates of a moving particle at any time are given by $x=a t^2$ and $y=b t^2$. The speed of the particle at any moment is [DPMT 1984; CPMT 1997]

At what height over the earth's pole, the free fall acceleration decreases by one percent $($ assume the radius of earth to be $6400\ \mathrm{km})$