At what distance from a convex lens of focal length `30cm`an object should be placed so that the size of image be`(1)/(4)`that of object?

At what distance from a concave mirror of focal length 25 cm should an object be placed so that the size of image is equal to the size of the object.

An object is placed at 30 cm from a convex lens of focal length 20 cm. State the nature and the size of the image relative to that of the object.

A point object O is placed at a distance of 20 cm from a convex lens of focal length 10 cm as shown in the figure. At what distance x from the lens should a convex mirror of focal length 60 cm, be placed so that final image coincide with the object?

A point object O is placed at a distance of 20 cm from a convex lens of focal length 10 cm as shown in the figure. At what distance x from the lens should a convex mirror of focal length 60 cm, be placed so that final image coincide with the object?

Point object O is placed at a distance of 20cm from a convex lens of focal length 10cm as shown in Figure., At what distance x from the lens should a concave mirror of focal length 60cm, be placed so that the final image coincides with the object?

At what distance should be placed from a convex lens of focal length 15 cm to obtain an image three times the size of the object?

At what distance should an object be placed from a convex lens of focal langth 15 cm to obtain an image three times the size of the object ?