A beam of light incident on a thin concave lens parallel to its principal axis diverges and appears to come from a point on the principal axis. Name the point. Draw a ray diagram to show it.
How will you differentiate between a convex and a concave lens by looking at (i) a distant object, (ii) a printed page?
An object is placed on the axis of a lens. An image is formed by refraction in the lens. For all positions of the object on the axis of the lens, the positions of the image are always always between the lens and the object Draw a ray diagram to show it.
State the changes in the position, size and nature of the image of an object when brought from infinity up to a concave lens. Illustrate your answer by drawing ray diagrams.
How does the action of a convex lens differ from that of a concave lens on a parallel beam of light incident on them? Draw diagram to illustrate your answer.
a) name the lens which always forms an erect and virtual image.
(b) state whether the image in part (a) is magnified or diminished.