Q 12-09-037JEE MainEasy
Find the focal length, in cm, of a plano-convex lens of refractive index $1.5$ whose curved surface has a radius of $15$ cm.
Numerical value type. Enter your answer.
Answer: 30
$\dfrac{1}{f} = (1.5 - 1)\dfrac{1}{15} = \dfrac{1}{30}$, so $f = 30$ cm.
Solution by Sreeraj P, M.Sc Physics