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Question: Magnification of a concave lens is A. \( > 0{\text{ and }} < 1\) B. \( > 1{\text{ or }} < \-...

Magnification of a concave lens is

A. >0 and <1 > 0{\text{ and }} < 1
B. >1 or <\-1 > 1{\text{ or }} < \- 1
C. >−1 and <1 > - 1{\text{ and }} < 1
D. Insufficient information

Explanation

Solution

In case of lens usually there are two types used. Concave lens and convex lens. All will serve different purposes. Properties of different lenses are different. In the case of concave lenses they always form virtual images. While convex lenses form both virtual and real images. Inverted image in the sense it is real.

Formula used:
∣m∣=hiho\left| m \right| = \dfrac{{{h_i}}}{{{h_o}}}

Complete answer:
When an object is placed in front of the lens the rays from the object passes through the lens and suffers refraction and image is formed. The position where image forms and the nature of the image formed depends upon the type of lens we use.
Various positions of placing an object in front of a convex lens gives us various positions of images.
If an object is placed between the pole and focus of the convex lens then image will be formed on the same side of the lens. That image formed can be enlarged and virtual and erected.
Now if we place an object between focus and center then the image is formed away from the center and the image will be real and inverted. The size of the image will be bigger than an object.
For concave lenses, there is always a diminished virtual image formed on the same side of the lens.
Magnification is given as ∣m∣=hiho\left| m \right| = \dfrac{{{h_i}}}{{{h_o}}} which is the ratio of height of image and height of object.
In case of a concave lens the image formed will be diminished. So magnification will definitely be less than 1. The image formed will be on the same side of the object and erect. So magnification must be positive. So magnification is >0 and <1 > 0{\text{ and }} < 1.

Hence option A is correct.

Note:
The distance of image from the lens will be less than distance of object from the lens. Then only magnification will be less than one. The magnification of convex lens will be analogous to concave mirror while magnification of concave lens will be analogous to convex mirror.