Question

What does Snell’s law become at the critical angle?

Options

• \[n_1\sin 90^\circ=n_2\sin 90^\circ\]

• \[n_1\sin i_c=n_2\sin i_c\]

• \[n_1\sin i_c=n_2\sin 90^\circ\]

• \[n_1\sin 90^\circ=n_2\sin i_c\]

Answer 1

At the critical angle, substitute \[i=i_c\] and \[r=90^\circ\] into Snell’s law. This gives \[n_1\sin i_c=n_2\sin 90^\circ\].