A virtual, erect and magnified image of an object is to be obtained with a convex lens. For this purpose, the object should be placed:

A converging lens is used to produce an image of an object on a screen. What change is needed for the image to be formed nearer to the lens?

A convex lens of focal length 8 cm forms a real image of the same size as the object. The distance between object and its image will be:

A burning candle whose flame is 1.5 cm tall is placed at a certain distance in front of a convex lens. An image of candle flame is received on a white screen kept behind the lens. The image of flame also measures 1.5 cm. If f is the focal length of convex lens, the candle is placed:

A lens of focal length 15 cm forms an erect image three times the size of the object. The distance between the object and image is:

(a) 20 cm (b) 16 cm

(c) 24 cm (d) 36 cm