Question

The power of a focal length is - 4D . state the state the nature of lens and any two characteristics of the image formed by a lens .

Answer 1

The lens is concave lens

It forms a small ,erect,and virtual image.

The lens is thick in corners and thin in between

Answer 2

$\bold{POWER \: OF\: LENS}$

When the incident light is deviated due to the refraction of lens is known as the power of lens.

Its measured in Dioptre D.

Given ,

Focal Lenght = -4D

$\bold{NATURE \: OF\: LENS}$

The lens which produces negative power is concave lens. Lens is of diverging nature ,such that when the ray of light passed through the lens after refraction appears to be diverging away from the lens.

$\bold{CHARACTERISTICS \: OF \: IMAGE \: FORMED}$

▶The image formed is always virtual (when rays of light dont actually meets but are produced so that they can meet) and formed on the same side of the object.

▶The image is always diminished.

▶The image is always erect.