Question

a) A heat source sits on the bench and can be treated as a 100 W spherical EM wave. You sit 3.4 m from the source. What infrared intensity do you experience in W/m²?

b) The heater is then placed in a parabolic mirror that puts all of the EM radiation in a perfectly collimated beam 70 cm in diameter. When the mirror is aimed at you, what intensity do you feel in W/m²?

Answer 1

Power P= l00 w Distanle r=3.4m Intemsity I=- P |00 %3D 4(3.1415)(3.4) =|0.6883 w/m? D diameter d= = 70 Cm Yadius r'= =35(m =0.35m Area of (Yoss sechom A=4 1(Y' A = 4(3.1415)(0.35)= 1.539 m² 100 -64.96 W/m?/ Intonsity I'' P 1.539