Difference between the convex lens and the concave lens
| CONVEX LENS | CONCAVE LENS |
| Definition | |
| A convex lens Is a piece of transparent material which is thick at the Centre and thin at the edges | A concave lens is a piece of transparent material which is thin at the Centre and thick at the edges. |
| Nature | |
| Convex lenses are called converging lenses because they converge the light.
| Concave lenses are called diverging lenses because they diverge the light.
|
| Focal length | |
| Its focal length is positive. | Its focal length is negative. |
| Use | |
| It is used for the Correction of Long-sightedness. | It is used for the correction of shortsightedness.
|
CONVEX LENS
It is a lens which is thick at the Centre and thin at the edges. It converges a parallel beam of light at a point and hence is called a converging lens.
TYPES OF CONVEX LENS
(a) Double Convex Lens
Both the surfaces of a double convex lens are convex.
(b) Plano Convex Lens
One of the two surfaces of such a lens is plane and the other is convex.
TYPES OF CONCAVE LENS
(a) Double Concave Lens
Both the surfaces of a double concave lens are concave.
(b) Plano Concave Lens
One of the two surfaces of such a lens is plane and the other is concave.
(c) Convex-Concave Lens
One of the two surfaces of such a lens is concave and other is convex.
