Question

The intensity of light produced by a light source varies

Answer 1

Answer:

45 foot-candles.

Explanation:

I ∝ 1d2⇒I=kd2

where k is a proportionality constant.

We can solve this problem in two ways, either solving for k and subbing back in or by using ratios to eliminate k. In many common inverse square dependences k can be quite a lot of constants and ratios often save on calculation time. We will use both here though.