Question

If i and r respectively denote angle of incidence and angle of refraction. If the angles are small, then the correct graph between i and r is shown by:

Options

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Answer 1

Explanation: 

For small angles,

\[ \sin i \approx i,\qquad \sin r \approx r \]

From Snell’s law,

\[ \frac{\sin i}{\sin r}=\mu \]

So, for small angles,

\[ \frac{i}{r}=\mu \]

Thus,

\[ i \propto r \]

Therefore, the graph between \(i\) and \(r\) is a straight line passing through the origin.