One half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Draw ray diagram to justify your answer.

The convex lens will form a complete image of an object, even if its one-half is covered with black paper. It can be understood by the following two cases: Case I: When the upper half of the lens is covered: In this case, the rays of light coming from the object will be refracted by the lower half of the lens. These rays meet at the other side of the lens to form the image of the given object, as shown in the figure.

Case II: When the lower half of the lens is covered:In this case, a ray of light coming from the object is refracted by the upper half of the lens. These rays meet at the other side of the lens to form the image of the given object, as shown in the figure.

The only difference between the image will be that it will have less intensity.