1. It is formed by the actual meeting of reflected (or refracted) rays. 2. It can be obtained on the screen. 3. It is always inverted. 4. lt is formed by concave mirror or convex lens.
1. It is formed when reflected (or refracted) rays appear to meet when produced backward. 2. It cannot be obtained on the screen. 3. It is always erect. 4. It is formed by concave, convex and plane mirrors (or concave and convex lenses).