Question

After using \[\sin 90^\circ=1\], which equation relates the critical angle to the refractive indices?

Options

• \[n_2\sin i_c=n_1\]

• \[n_2\sin i_c=1\]

• \[n_1\sin i_c=n_2\]

• \[n_1\sin i_c=1\]

Answer 1

At the critical angle, Snell’s law gives \[n_1\sin i_c=n_2\sin 90^\circ\]. Because \[\sin 90^\circ=1\], the equation simplifies to \[n_1\sin i_c=n_2\].