Question

A heat lamp emits infrared radiation whose rms electric field is Erms = 2500 N/C. (a) What is the average intensity of the radiation? (b) The radiation is focused on a person's leg over a circular area of radius 4.5 cm. What is the average power delivered to the leg? (c) The portion of the leg being irradiated has a mass of 0.34 kg and a specific heat capacity of 3500 J/(kg·C°). How long does it take to raise its temperature by 2.0 C°? Assume that there is no other heat transfer into or out of the portion of the leg being heated.

Answer 1

(a) Average intensity of radiation

(b) Average power delivered to the leg is

(c) Heat required to raise the temperature of a mass with specific heat capacity is

time required is