Inverse formula of light intensity and distance (1 Viewer)

[x.Exhaust.x]

Would anyone happen to have a simple explanation for the inverse formula of light intensity and distance? (Intensity proportional to 1 / Distance^2). I need practice with this, because I know it'll pop up in the half yearly exam.

Thanks.

 

[st1m]

yeah I1/I2= D1/D2 i think its that

just pop it in this formula and cross multuply

cya

P.s im in a hurry lol sorry for the minimum explaination

 

[bored of sc]

inverse is the opposite - so the opposite to 1/d^2 is -d^2 (negative reciprocle)

no?

P.S I don't do physics but I am just trying to help - probably confusing everyone not to mention myself :apig:

 

[x.Exhaust.x]

inverse is the opposite - so the opposite to 1/d^2 is -d^2 (negative reciprocle)

no?

P.S I don't do physics but I am just trying to help - probably confusing everyone not to mention myself :apig:

Thanks man you did your best , but that wasn't what I was asking. I may as well ask the teacher.

Thanks to the both of you =]

 

[Felix Jones]

basically what it means is that as the distance from the source of the light increases the intensity decreases (because it covers more area). for example think about a torch shining its light through a small hole. if u bring a papers and place it in front of the hole, the brightness of the light increases (intensity) but the area covered decreases. when u move away the paper, u increase the area it covers, hence when it covers more area the intensity decreases (less bright).

i'll give u a numerical explanation if that didn't help:

Question:
-if the light intensity at a distance (a) from a light source is 45 lux (unit for light intensity)
-then what would be the intensity of light if you:
a)tripled the disdance
b)halved
c)increases it by tenfold?

answer:
a)just chuck 3 in the formula (1/d^2) and u would get (1/9)
this means that the intensity of light is now 1/9 th of what it was before, and 45 *(1/9) =5 lux.

b) same as before chuck those numbers in the formula so (1/(0.5)^2)= 4, there fore the intensity will be four times greater. hence the intensity is: 45*4= 180 lux.

c) same as before, but try this urself.


Good Luck!!!