A source of light and a screen are placed 90 cm apart. Where should a convex lens of 20 cm focal length be placed in order to form a real image of the source on the screen ?

Two point sources P and Q are 24cm apart. Where should a convex lens of focal length 9cm be placed in between them so that the images of both sources are formed at the same place?

Two point surces S_(1) and S_(2) are 24 cm apart. Where should a convex lens of focal length 9 cm be placed them , so that the images of both sources are formed at the same place ?

Two point sources S_(1) and S_(2) are 24 cm apart. What should a convex lens of focal length 9 cm be placed between them so that the images of both sources formed at the same place ?

Two point sources S_(1) and S_(2) are 24 cm apart. What should a convex lens of focal length 9 cm be placed between them so that the images of both sources formed at the same place ?

An object is placed at a distance of 75 cm from a screen. Where should a convex lens of focal length 12 cm be placed so as to obtain a real image of the object?

An object is placed at a distance of 75 cm from a screen. Where should a convex lens of focal length 12 cm be placed so as to obtain a real image of the object ?