What is evaporated from the watch glass? Is there any residue on the watch glass?

The acid used for etching the glass is

Do they get formed if there is no ice in the glass?

What is the relative density of glass ?

How glass is obtained?

Explain why The angle of contact of mercury with glass is obtuse. While that of water with glass is acute .

Take some paddy grains and soak them in water for one day. Take them into watch glass and sow them in soil. After that observe the radicle and plumule with the help of hand lens and draw the picture of it.

Light from a point source in air falls on a spherical glass surface (n = 1.5 and radius of curvature = 20 cm). The distance of the light source from the glass surface is 100 cm. At what position the image is formed?