Question

The intensity of the waves from a point source at a distance d from the source is I. At what distance from the sources is the intensity equal to 2I

Answer 1

Answer:
`d'=(d)/(√(2))`

Step-by-step explanation:

Intensity of the waves from a point source can be given by Power divided by surface area.

For P Power source and at a distance d from source Intensity is given by

`I=(P)/(\pi\cdot d^2)--------1`

when intensity is 2I then it is at a distance of let say d'

`2I=(P)/(\pi\cdot d'^2)--------2`

Divide 1 and 2 we get

`(I)/(2I)=(P)/(\pi\cdot d^2)* (\pi\cdot d'^2)/(P)`

`(1)/(2)=((d')/(d))^2`

`(d')/(d)=(1)/(√(2))`

`d'=(d)/(√(2))`