A small surface of area A1 = 3cm2 emits radiation as a blackbody at T1 = 1000 K.A radiatio...

A small surface of area A1 = 3cm2 emits radiation as a blackbody at T1 = 1000 K.A radiation detector (A2) is placed normal to the direction of viewing from surface A1 at a distance L, as shown in the figure. If the radiation detector is measuring an irradiation of 100 W/m2, determine the distance between the radiation detector and surface A1.