Question

Glass is known to be transparent material. But ground glass is opaque and white in colour. Why?

Answer 1

Glass is the smooth surface whereas, the ground (past tense of the grind) glass is very rough and flat surface and so it does not have the smooth surface and has lots of scratches on it which scatters the light falling on it without allowing the light to enter and pass through it.

Complete step by step answer:
Glass is the transparent material and allows passing of the light through it. Due to the microscopic unevenness of the ground glass, when the light falls on its rough surface gets reflected and scattered in all the directions and does not allow the light to pass through it. During the transmission, the ground glass has the effect of providing the glass the translucent by the scattering of the light and thus blurring the visibility and this type of reflection where the light comes out in various directions is known as the diffused reflection. Hence the ground glass seems to be opaque and white in colour.

Note: Know the basic difference between the types of materials to justify these types of statements.
-The materials through which light penetrates completely are known as the transparent material. For example – Clear glass and clear air.
-The material which allows only some of the visible light to pass through it is known as the translucent materials. For Example – Sunglasses and gemstones.
-The materials which do not allow any light to pass through it are known as the opaque. For Example – Wood, iron.