Question

If the distance increases from 30 inches to 60 inches, what happens to the exposure?

1) It is doubled
2) Decreases to ¼ of the original beam
3) It increases by a factor or 4
4) Decreases to ¬Ω of the original beam

Answer 1

When the distance from a light source is doubled, the illuminance or exposure decreases to one quarter of its original value due to the inverse square law.

Step-by-step explanation:

If the distance increases from 30 inches to 60 inches, the exposure, or illuminance, of light changes according to the inverse square law. This law states that the illuminance is inversely proportional to the square of the distance from the light source. In simpler terms, if you double the distance from the light source, the illuminance will decrease to one quarter of its original value because (2)^2 = 4. Therefore, in this case, if the distance is increased from 30 inches to 60 inches, the exposure or illuminance decreases to ¼ of the original beam. So, the correct answer would be that the exposure decreases to ¼ of the original beam.