MCQ
If $\hat{i}$ denotes a unit vector along incident light ray, $\hat{r}$ a unit vector along refracted ray into a medium of refractive index $\mu$ and $\hat{n}$ unit vector normal to boundary of medium directed towards incident medium, then law of refraction is
  • A
    $\hat{i} \cdot \hat{n}=\mu(\hat{r} \cdot \hat{n})$
  • B
    $\hat{i} \times \hat{n}=\mu(\hat{n} \times \hat{r})$
  • $\hat{i} \times \hat{n}=\mu(\hat{r} \times \hat{n})$
  • D
    $\mu(\hat{i} \times \hat{n})=\hat{r} \times \hat{n}$

Answer

Correct option: C.
$\hat{i} \times \hat{n}=\mu(\hat{r} \times \hat{n})$
Snell's law in vector form is $\hat{i} \times \hat{n}=\mu(\hat{r} \times \hat{n})$

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