Where should an object be placed in front of a convex lens of focal length 0.12 m to obtain a real image of size three times the size of the object, on the screen?

A lens forms the image of an object placed at a distance of 45 cm from it on a screen placed at a distance 90 cm on the other side of it.

(a) Name the kind of lens.

(b) Find : (i) the focal length of lens, and (ii) the magnification of the image.

An illuminated object lies at a distance 1.0 m from a screen. A convex lens is used to form the image of the object on a screen placed at a distance of 75 cm from the lens.

Find —

(i) the focal length of lens, and

(ii) the magnification.

An object is placed at a distance of 20 cm in front of a concave lens of focal length 20 cm. Find —

(a) the position of the image, and

(b) the magnification of the image