Where should an object be placed from a converging lens of focal length 20 cm, so as to obtain a real image of magnification 2?

Where should an object placed from a conveging lens of focal length 20 cm,so as to obtain a real image of magnification 2?

Where should an object be placed from a converging lens of focal length 10 c, so as to obtain a virtual image of magnification 2 ?

Calculate the distance of an object of height h from a concave mirror of focal length 10 cm so as to obtain a real image of magnification 2 .

An object is placed 80 cm from converging lens of focal length 25 cm. What is the nature of image?

At what distance from a converging lens of focal length 12 cm must an object be placed in order than an image of magnification 1 will be produced?

At what distance should an object be placed from a lens of focal length 25 cm to obtain an image on a screen placed at a distance of 50 cm from the lens ? What will be the magnification produced in this case?

Where should an object be placed in front of a concave mirror of focal length 15 cm to have a magnification of 3 in case of (a) real image (b) virtual image ?