Q. If $\widehat{i}$ denotes a unit vector along incident light ray, $\widehat{r}$ a unit vector along refracted ray into a medium of refractive index $\mu$ and $\widehat{n}$ unit vector normal to boundary of medium directed towards incident medium, then law of refraction is
A) $\widehat{i}.\widehat{n} = \mu(\widehat{r}.\widehat{n})$
B) $\widehat{i} \times \widehat{n} = \mu(\widehat{n} \times \widehat{r})$
C) $\widehat{i} \times \widehat{n} = \mu\left( \widehat{r} \times \widehat{n} \right)$
D) $\mu\left( \widehat{i} \times \widehat{n} \right) = \widehat{r} \times \widehat{n}$
Explanation
(c) Snell’s law in vector form is $\widehat{i} \times \widehat{n} = \mu(\widehat{r} \times \widehat{n})$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.