Question

A 100 watt bulb emits light in all directions. The distance R from the bulb is equal to 1.0 meter.

Complete the table below with calculated values of intensity of the bulb.



Distance from Source Intensity (W/m2)
R ?

2R ?

3R ?


c) If the bulb was replaced by a 75 watt bulb, at position 2R the intensity would be?

Answer 1

this is really nonsense. 100 watt light bulbs do not radiate 100 watts of luminous energy. So using the inverse square law is silly, at best.