Theoretical Optics Review Quiz 1

Find the illuminance of the table 4 m directly under a 100 cd electric lamp.

• 100 mc

• 4 lumen

• 6.25 mc

• 6.25 steradians

An unknown lamp placed 6m from a photometer screen provides the same illumination as an 80-cd lamp placed 4m from that same screen. What is the candle power of the unknown lamp?

• 120 cd

• 53.33 cd

• 80 cd

• 480 cd

What illuminance will be given on a desk by a 36-cd fluorescent lamp 1 foot long placed 18 inches above the surface?

• 6 fc

• 48 fc

• 0.75 steradians

• 32 cd

An opaque globe 2 feet in diameter is located 5 ft from a point source. If a screen is placed 10 ft. from the source, what will be the diameter of the shadow on the screen?

• 4ft

• 100ft

• 6ft

• 80ft

A ball with a diameter of 15 inches is 36 inches from a light source whose diameter is 5 inc w, area hes. A screen is 19 inches behind the ball. Determine the area of penumbra

• 2.ft

• 4.90ft2

• 2.66ft2

• 2.24ft2