Question

how will you identify convex lens and concave lens without touching ?

Answer 1

Hey mate !!!

The basic difference between a CONCAVE lens and a CONVEX lens is that

• Convex lens always forms an enlarged image of the object

Whereas

• Concave lens forms a diminished image of the object.

Activity-

Take the lenses and put the lenses on a printed book in such a way that you can see the printed letters clearly .

Here , two types of images will be formed-

▪ enlarged
▪diminished

If the letters of the book appear enlarged, it is a convex lens .

If they appear diminished, it is concave lens.

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Hope this helps!!!

Answer 2

We can differentiate between a convex and concave lens by seeing the image.

• On keeping the lens near a printed page, if letters appear magnified, the lens is convex and if the letters appear diminished, the lens is concave.
• On seeing a distant object through the lens, if its inverted image is seen, the lens is convex and if an upright image is seen, the lens is concave.