Question

Distinguish between convex and concave lens without touching it

Answer 1

Place it very near to a paper.... If it produces a diminished image then it is concave lens and if it produces a magnified image then it's a convex lens.

When we place an object between focus and optical centre of a convex lens, we obtain a magnified and a virtual image.
# A student of class 10
# hope it 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.