Question

The spectrum of the Sun as seen on the ground is different from that which arrives that the top of the atmosphere True False

Answer 1

It is true. The spectrum of the Sun's radiation is different on the Earth's surface when compared with the atmosphere.

This is probably due to the effect of Earth's atmosphere on the sun's radiation. The sunlight that reaches the Earth's surface contains around 52% - 55% of the infrared radiation that has a wavelength of above 700 nm, 42% - 43% of the visible radiation that is 400 - 700 nm, and 3% - 5% of the ultraviolet radiation that is below 400 nm. 

At the top layers of the atmosphere, the sunlight is more intense by almost 30%. This atmospheric layers will have sunlight spectrum that contains about 8% of the ultraviolet (UV) radiation and most of the extra UV in this layer consists of the short-wave ultraviolet rays that are biologically damaging.