How are gems different from regular minerals? gems are softer than regular minerals. regular minerals are more beautiful than gems. gems are rarer than regular minerals. regular minerals are less malleable than gems.

Option (3)

Explanation:

Gemstones are those pieces of minerals that are being cut and are in their polished form. They are economically valuable and the factors that control the value of these gemstones are color, cutting in perfect shapes, luster, durability, and rarity.

Whereas, regular minerals are those that occur naturally and are inorganic in nature. They are comprised of one or multiple elements. They are commonly found on earth.

From the given question, the best option to differentiate between regular minerals and gemstones is that gemstones are very rare and are economically very valuable, in comparison to the common regular minerals.

Thus, the correct answer is option (3).

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.