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 56 ft from a light is 2.7 foot-candles, find the intensity on a screen 70 ft from the light.

The intensity on a screen 70 ft from the light is 1.728 foot candle.

Step-by-step explanation:

Given that,

The magnitude of  intensity of light varies inversely as the square of the magnitude of distance D from the source.

That is

Then,

Given that,

The magnitude of intensity of illumination on a screen 56 ft from a light is 2.7 foot-candle.

Here,

=2.7 foot-candle, = 56 ft

=?, = 70 ft.

foot-candle

The intensity on a screen 70 ft from the light is 1.728 foot candle.

it’s the first one your welcome

it is 10.6 according to my calculations