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

question 366

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

---

Definitions:

Economic

Relating to the system of production, distribution, and consumption of goods and services in a society, and the study of how scarce resources are allocated.

Biomass

The total mass of all living organisms in a given area or volume; it can also refer to plant or animal matter used as fuel.

Clear-cut

A forestry or logging practice where all trees in an area are uniformly cut down, often used for timber production but criticized for environmental impact.