Question

what is the inverse square law?? Please thoroughly describe what it means

Answer 1

if F is inversely proportional to r

\[F\propto r^{-2}\]
\[F=\frac k{r^2}\]

Answer 2

i dont understand it though...

Answer 3

can you use simple math to explain

Answer 4

for example the intensity of a light source is inversely proportional to the distance form the light source.

Answer 5

the light flux diverges the further fro the source you are

Answer 6

another example would be a music speaker

when you are close the sound is intense, the further away form the speaker you are the softer the sound

Answer 7

but what does it mean if it decreases by the square of the distance

Answer 8

The inverse square law can be described as follows:
The intensity of a field of radiation is inversely proportional to the square of the distance from the source of the radiation. The inverse square law applies to any system with spherical wavefront and negligible energy absorption.

Answer 9

it means, the thing spreads in 3D space. so it becomes less intense as it propagates...
lets compare what happens if the same thing spreads in 2D, 1D :
2D : reduces 1/r
1D : constant. it never reduces. propagates forever with out losing any intensity


makes sense ?

Answer 10

still confused, trying to wrap my head around this. The math is SUPER easy im just trying to figure out the concept..

Answer 11

so if u have a light source and you increase your distance it will decrease by the square of the distance

say distance is 2

1/2^2

so 1/4

Answer 12

Say you are at a lamp,\[I=\frac{10}{r^2}\]
the intensity of the light from the lamp is 10 lux when you are 1 meter away
\[I=\frac{10}{1^2}=10 \]

when you are 2 meters away the lux is
\[I=\frac{10}{2^2}=2.5 \]
when you are 3 meters away the lux is
\[I=\frac{10}{3^2}=1.11 \]

when you are 15 meters away the lux is
\[I=\frac{10}{15^2}=0.044\]

Answer 13

Makes perfect sence thanks~

Answer 14

the gravitational force of attraction between masses has a inverse square relation to the radius between the masses

\[F=G\frac{m_1m_2}{r^2}\]

Answer 15

meaning that the gravitational force decreases by the square of the distance

Answer 16

exactly