The minimum number of light rays needed to form the image of an object in a convex lens is
In olden days, the convex lens was used to ignite by allowing the sun rays to be focused on the object to be ignited. The lens converges the heat rays just like converging the light rays. What kind of image is formed by the convex lens?
Fill in the following blanks with suitable words : (a) A convex lens ___ rays of light, whereas a concave lens___ rays of light. (b) Lenses refract light to form images : a ___lens can form both real and virtual images, but a diverging lens forms only___ images.