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

Question

asked Dec 19, 2020 175k views

1 Answer

Neongrau · Answer 1 · 2020-12-24T03:09:05+0000

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))