Question

The intensity I of light produced by a light source varies inversely as the square of the distance d from the source. If the intensity of light produced 3 metres from a light source is 75 Cd, find the intensity of light produced 5 metres from the same source

Answer 1

27 cd

Explanation:

(75 cd)(3m)^2 = (x)(5m)^2

x = (75 cd)(9 m^2)/(25 m^2)

= 27 cd