Question

Write the difference between convex lens and concave lens

Answer 1

 

Concave

Convex

Structure

A concave lens is thinner in the middle and thicker at the edges.

A convex lens is thicker in the middle and thinner at the edges.

Other name

Diverging Lens

Converging Lens

Images Formed

Virtual, upright and smaller than the object between object and the lens. (regardless of the object's position)

Real , inverted, smaller than object, - object at F

Real , inverted, same size as object, - object at 2F

Real , inverted, larger than  object, object between 2F and F

No image -  object at F

Virtual, upright, larger than object – behind object on the same side of the lens

Meaning

Concave means “hollowed or rounded”.

Convex means “curved or rounded like the outside of a sphere or circle”.

In Spectacles

Used for the correction of problem in short sight.

Used for the correction of problem in long sight.

Applications

Glasses (to correct for short sight), spy holes in doors, some telescopes, back window of coaches, etc.

Eye, camera, overhead projector, focus sunlight, projector microscope, simple telescope, glasses (to correct for long sight), magnifying glass, etc.

Focal Length

Negative

Positive

Answer 2

Concave mirror is the mirror with reflecting surface as the inner part.
They are used by ENT doctors to examine the various organs.
Convex mirror is the mirror with reflecting surface as the outer part.
They are used as the side mirrors in vehicles which help the drivers to see the traffic behind.