The intensity on a screen 20 ft from the light will be 0.125-foot candles.
<h3>What is the distance?</h3>
Distance is a numerical representation of the length between two objects or locations.
The intensity I of light varies inversely as the square of the distance D from the source;
I∝(1/D²)
The ratio of the intensity of the two cases;

Hence, the intensity on a screen 20 ft from the light will be 0.125 foot-candles
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Answer:
Visible Light and Radio waves
Explanation:
The earth's atmosphere is transparent to a few windows in the electromagnetic spectrum. it is completely transparent to allow observation from the ground in visible light rang 380 to 740 nano meters. Also in the range of radio wave as communication are done from space to ground in the form of radio waves.
it is Partially transparent to Microwave and infrared range.
Answer:
3, 4, 2
Explanation:
I can't see the final ones.
I'm stuck on the same question, as well :(
Answer:
When work is positive, the environment does work on an object.
Explanation:
According to the work-energy theorem, the net work done by the forces on a body or an object is equal to the change produced in the kinetic energy of the body or an object.
The concept that summarizes a concept related to the work-energy theorem is that ''When work is positive, the environment does work on an object.''