Which has more power, a thick concave lens or a thin convex lens, made of the same glass? Give reason for your choice.

Draw ray diagrams to represent the nature, position and relative size of the lens for the object placed: a) at 2F_(1) , b) between F_(1) and the optical center O of the lens. Which of the above two cases shows the use of convex lens as a magnifying glass? Give reasons for your choice.

What is the sign of the power of (i) a convex lens (ii) a concave lens ?

A convex lens is known as a converging lens. Give reason.

Which portion of a bi-focal lens is (a) a concave lens (b)a convex lens ?

A concave lens is called a diverging lens. Give Reason

When a thin convex lens is put in contact with a thin concave lens of the same focal length (f), then the resultant combination has focal length equal to

When a thin convex lens is put in contact with a thin concave lens of the same focal length (f), then the resultant combination has focal length equal to

A beam of parallel rays is brought to a focus by a plano-convex lens. A thin concave lens of the same focal length is joined to the first lens. The effect of this is