A point source of light is placed at a distance of 2f from a converging lens of focal length f. The intensity on the other side of the lens is maximum at a distance

Four modifications are suggested in the lens formula to include the effect of the thickness t of the lens. Which one is likely to be correct?

A double convex lens has two surfaces of equal radii R and refractive index m=1.5. We have,

A parallel beam of light is incident on a converging lens parallel to its principal axis. As one moves away from the lens on the other side on its principal axis, the intensity of light

A symmetric double convex lens is cut in two equal parts by a plane perpendicular to the principal axis. If the power of the original lens was 4 D, the power of a divided lens will be