Question

rays of light are incident on a concave lens of refractive index n from a medium of refractive index n 1 . after refraction it remains undeviated as shown in figure . then.
(1) n1 =n
(2) can't be possible
(3)n1 <n
(4) n1> n​

Answer 1

Answer:

CORRECT ANSWER IS OPTIONS NO

(3)

Answer 2

Answer:

No deviation in the path of the light ray, if there is no change in the refractive index of the medium,  $n_1 =n$.

Explanation:    

Given the rays of light are incident on a concave lens of refractive index $n$ from a medium of refractive index $n_1$.

And after refraction it remains undeviated.

• When light is passing from one medium to the another medium, the direction of the light ray changes from the surface of separation. This phenomenon is called refraction.
• The change in the direction of light is due to the change in speed of light in a medium.
• Light travels at different speeds in different media.
• The ratio of speed of light through vacuum to the speed of light in medium is given by the refractive index, $n=\frac{c}{v}$.
• So, if there is no change in the medium, then there is no deviation in the path of the light ray.

Hence, if there is no deviation in light rays after refraction through a concave lens of refractive index n from a medium of refractive index $n_1$, then $n_1 =n$.

So, correct answer is option 1.