Chapter 18.2, Problem 22SSC

(a)

To determine

The lenses from given figure which are convex or converging lenses.

Explanation of Solution

Introduction:

Parallel light rays are converged by converging lens at focal point of focus.This lens can form real or virtual image.

  

If either the sides or one side of the lens is curved, then it is converging lens. Also, converging lens have center part thicker than its edges. Here, in figure a andc lens have curved surface, so they are converging or convex lens.

Conclusion:

Figure a and care converging.

(b)

To determine

The lenses from given figure which are concavediverging lenses.

Explanation of Solution

Introduction:

Parallel light rays are diverging by diverging lens at focal point of focus.This lens can form real or virtual image.

  

If both sides or one side of the lens is curvedinwards then it is diverging lens. Also diverging lenses haveedges part thicker than its center. Here in figure, b and d lens have curved surface so they are diverging or concave lens.

Conclusion:

Figure b and d are diverging.