Question

The focal length of a normal eye lens is about

• A. $1\text{mm}$
• B. $2\text{cm}$
• C. $25\text{cm}$
• D. $2.5\text{m}$

Answer 1

The correct option is B $2\text{cm}$

A normal eye has retina $2\text{cm}$ behind the eye lens for the object that are at large distance.

So, when parallel rays are coming they form image at focus and to make image at retina focal length should be about $2\text{cm}$.

Hence, $\left(B\right)$ is the correct answer.