The Intensity I of Light Varies Inversely as the Square $1 \frac { 1 } { 8 }$

Multiple Choice

The intensity I of light varies inversely as the square of the distance D from the source. If the intensity of illumination on a screen 5 ft from a light is 2 foot candles, find the intensity on a screen 20 ft from the light.

A) $1 \frac { 1 } { 8 }$ foot-candles
B) $\frac { 1 } { 8 }$ foot-candle
C) $\frac { 1 } { 9 }$ foot-candle
D) 2 foot-candles