Which statement is true? a) geothermal power plants use the renewable resource of heat from within the earth to generate electricity. b) hydroelectric energy uses the energy from the sun, which is a renewable resource. c) oil is a nonrenewable resource that is hardly ever used, so there is not a concern of depleting the earth's supply. d) solar energy is a nonrenewable resource that is used by many countries all over the world.

A). Geothermal power plants use the renewable resource of heat from within the Earth to generate electricity.

Explanation:

Geothermal energy is the energy which is obtain in the form of heat liberated from water released from the earth geosphere. The hot mantle causes the boiling of the groundwater which is liberated from the hot spring. It is a renewable source of energy which means it is obtained from resource which can be replenished and can be used again. This energy is used to generate electricity.

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.