Question

A spherical minor and a thin spherical lens have each focal length of $15cm$. The mirror and the lens are to be:

• A. both concave
• B. both convex
• C. the mirror is concave and the lens is convex
• D. the mirrors is convex and the lens is concave

Answer 1

Answer: (B)

both convex

$\begin{array}{c}\text{Focal length}=+15cm\\ \text{the focal length is positive for convex}\\ \text{mirror and Convex lens.}\\ \text{SO (B) Both convex is the right option.}\end{array}$