The height of the image formed by a converging lens on a screen is $8\,cm$. For the same position of the object and screen,another image of size $12.5\,cm$ is formed on the screen by shifting the lens. The height of the object is...

In order to obtain a real image of magnification $2$ using a converging lens of focal length $20 \ cm,$ where should an object be placed in $cm$?

$A$ convex lens has its radii of curvature equal. The focal length of the lens is $f$. If it is divided vertically into two identical plano-convex lenses by cutting it, then the focal length of the plano-convex lens is ($\mu =$ the refractive index of the material of the lens).

$A$ convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens material. Then its focal length will

The distance between an object and its image produced by a converging lens is $0.72 \ m$. The magnification is $2$. What will be the magnification when the object is moved by $0.04 \ m$ towards the lens?

$A$ parallel beam of light is incident on a converging lens parallel to its principal axis. As one moves away from the lens on the other side along the principal axis,the intensity of light