Question

Out of the five incident rays shown in the figure find the three rays that are obeying the laws of refraction and may be used for locating the position of image formed by a convex lens:

• A. 1, 2 and 3
• B. 2, 3 and 4
• C. 3, 4 and 5
• D. 1, 2 and 4

Answer 1

The correct option is B 2, 3 and 4

The incident ray parallel to the principal axis pass through the focus of the lens after refraction and vice-versa. And the ray doesn’t deviate when it incident on optical centre.

Thus rays $2$ and $4$ obey the law of refraction.

Also the ray through the optical center of the lens passes undeviated i.e ray $3$ also obeys refraction law.

Thus option B is correct.