A wide slab consisting of two media of refractive indices $n_1$ and $n_2$ is placed in air as shown in the figure. A ray of light is incident from medium $n_1$ to $n_2$ at an angle $\theta$, where $\sin \theta$ is slightly larger than $\frac{1}{n_1}$. Take refractive index of air as $1$. Which of the following statement(s) is (are) correct?

• A

  The light ray enters air if $n_2=n_1$.
• Correct answer
  B

  The light ray is finally reflected back into the medium of refractive index $n_1$ if $n_2<n_1$.
• Correct answer
  C

  The light ray is finally reflected back into the medium of refractive index $n_1$ if $n_2>n_1$.
• Correct answer
  D

  The light ray is reflected back into the medium of refractive index $n_1$ if $n_2=1$.

Hence, the correct answer is options: 'B', 'C', 'D'.