When the person steps out of the shade she exposes about 1/3 of her exposed surface area to direct sunlight and the temperature of this exposed skin rises to 39°C. It is close to sunset, so the sun is shining more or less horizontally and the atmosphere attenuates its intensity to only 25% of its normal value of 1360 W m–2. On top of that, the person’s pale skin reflects 60% of the sun’s rays which are predominantly in the visible part of the electromagnetic wave spectrum. Estimate, just roughly, how the person’s overall radiative exchange of energy with her environment (including the sun) changes as a result of stepping out of the shade.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.

root word, prefixes, and suffixes

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2