The brightness of a light source decreases as the distance from the source increases. This relationship is described by the inverse square law, which states that the brightness of a light source is inversely proportional to the square of the distance from the source.
If the luminosity of a lightbulb is 100 W and the brightness is measured to be 0.01, then we can use the inverse square law to calculate the distance to the lightbulb.
The inverse square law can be expressed as:
B = L/(4πd^2)
where B is the brightness, L is the luminosity, and d is the distance.
Plugging in the given values, we get:
0.01 = 100/(4πd^2)
Solving for d, we get:
d = √(100/(4π*0.01))
d ≈ 15.9 meters
Therefore, the distance to the lightbulb is approximately 15.9 meters.