The focal length of a lens is (i) positive, (ii) negative. In each case, state the kind of lens.

Open in App

Solution

(i) The positive focal length of a lens indicates that it is a convex lens.
(ii) The negative focal length of a lens indicates that it is a concave lens.

Suggest Corrections

Similar questions

A convex lens made of glass of refractive index 1.5 has both surfaces of the same radius of curvature R. In case (i) the lens is immersed in a medium of refractive index 1.25 and in case (ii) it is immersed in a medium of refractive index 1.75. Then,

The power of a lens is + 2.0 D. Find its focal length and state the kind of the lens.

Why focal length of convex mirror and convex lens is positive while concave mirror and concave lens negative?

(a) An object 2 cm tall stands on the principal axis of a converging lens of focal length 8 cm. Find the position, nature and size of the image formed if the object is : (i) 12 cm from the lens (ii) 6 cm from the lens (b) State one practical application each of the use of such a lens with the object in position (i) and (ii).

Q. A equiconvex lens is cut into two halves along (i) XOX' and (ii) YOY' as shown in the figure.Let f,f′,f"f,f′f"be the focal lengths of the complete lens, of each half in case (i), and of each half in case (ii), respectively
Choose the correct statement from the following-

Join BYJU'S Learning Program

The focal length of a lens is (i) positive, (ii) negative. In each case, state the kind of lens.

(i) The positive focal length of a lens indicates that it is a convex lens. (ii) The negative focal length of a lens indicates that it is a concave lens.

(i) The positive focal length of a lens indicates that it is a convex lens.
(ii) The negative focal length of a lens indicates that it is a concave lens.