Question

if you are give three circular piece of glass how will you identify which one of them is a concave lens in which one of the convex lens and with which one just a piece of glass

Answer 1

by touching the pieces of glass you can identify the piece of glass
#for concave lens
u will feel a depression in the centre and edges will be thick
#for convex lens
tapering at the ends and thick at the centre
#for normal piece of glass
thickness remains the same at every point

Answer 2

Answer:

Explanation:

microscopes let us peer inside invisible worlds our eyes could never see, telescopes take us far beyond the Earth to the stars and planets of the night sky, movie projectors throw enormous images onto screens, and lighthouses cast reassuring beams of light far across the ocean. Amazing curves of glass or plastic called lenses make all these things possible. Let's take a closer look at what they are and how they work!