Solar Radiation|Variability of isolation at the surface of the earth

Solar radiation heat up

A radio station on the surface of the earth radiates 50 kW . If transmitter radiates equally in all directions avove the surface of the earth . Find the amplitude of electric field detected 100 km away :

The intensity of salr radiation just outside the earth's atmosphere is measured to be 1.4 kW//m^2 . If the radius of the sun 7xx10^8m , while the earth-sun distance is 150xx10^6km , then find i. the intensity of salr radiation at the surface of the sun. ii. the temperature at the surface of the sun assuming it to be a black body, iii. the most probable wavelength in solar radiation.

Solar radiation is an example of

Is it true that ozone, the deadly poison it is , shields the surface of the earth from UV radiation ?