Ray Optics Question 6
Question 6 - 25 January - Shift 2
An object is placed on the principal axis of convex lens of focal length $10 cm$ as shown. A plane mirror is placed on the other side of lens at a distance of $20 cm$. The image produced by the plane mirror is $5 cm$ inside the mirror. The distance of the object from the lens is $cm$.
Show Answer
Answer: (30)
Solution:
Formula: Lens Maker’s Formula
$f=10 cm$
$\frac{1}{v}-\frac{1}{u}=\frac{1}{f}$
$\frac{1}{15}-\frac{1}{-u}=\frac{1}{10}$
$\Rightarrow \frac{1}{u}=\frac{1}{10}-\frac{1}{15}$
On solving we get value of $u$ as $30 cm$.
