A source of light is used to illuminate a screen. 1 m from the source, the intensity of the light falling on the screen is 12 000 lux. Calculate the intensity on the screen at distances of:
(a) 2 m
(b) 3 m
(c) 4 m
I 1/I 2 = d^2 2/d^2 1
The Attempt at a Solution
I don't understand at all. I'm hoping you guys would be able to explain what I am meant to do here because the teacher fails at teaching.
Just give me the equation for (a) so that I have a better understanding of what the is going on which would hopefuly enable me to do (b) and (c).