Which two statements describe reasons that semiconductors must be included in a solar cell?
A. They form a zone of separation between the glass layer and the
terminal layer.
B. They provide a path through which released electrons move to
form an electric current.
c. They provide a path through which electrons exit the surface of
the cell and never return.
D. They provide a source of electrons to be released by the
photoelectric effect.

They provide a source of electrons to be released by the photoelectric effect, and They provide a path through which released electrons move to form an electric current.

Explanation:

A p e x

The answer is B. They provide a source of electrons to be released by the photoelectric effect, and D.They provide a path through which released electrons move to form an electric current.

Explanation:

I took AP EX quiz.

does anyone know or what?

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.