Consider the sun as an isotropic radiation source. Calculate the total power radiated by the sun in the frequency band of 54-60 MHz. The distance between the sun and the earth is approximately 1.5 × 108 km. Solution Power density=0.6*10-22W/m2-Hz Power density in 54-60MHZ=(60-54)*106*0.6*10-22W/m2=3.6*10-16W/m2 Total Power density radiated by sun=(60-54)*106*0.6*10-22*4*pi*(1.5*108*k)2=101.8W.