. A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen :
(a) half of the image will disappear (b) complete image will be formed
(c) intensity of the image will increase (d) intensity of the image will decrease
When upper half of the lens is covered, image is formed by the rays coming from lower half of the lens. Or image will be formed by less number of rays. Therefore, intensity of image will decrease. But complete image will be formed.