Which statement correctly describes mass-energy equivalence? all energy in the universe will be converted to an equivalent amount of mass. mass can decrease in nuclear changes without the production of energy. all energy in the universe is a result of mass being converted into energy. a large amount of mass is equivalent to a small amount of energy.

Explanation :

Mass-energy equivalence :

Albert Einstein gives a relation between the mass and the energy which is given by :

E is the energy of the object

m is the mass of the object

c is the speed of the light ()

Mass-energy equivalence states that any object has the same amount of mass as well as energy.

So, the correct option is (c) " All energy in the universe is a result of mass being converted into energy ".

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.