In the figure,$ABC$ is the cross-section of a right-angled prism and $BCDE$ is the cross-section of a glass slab. The value of $\theta$ so that light incident normally on the face $AB$ does not cross the face $BC$ is (given $\sin^{-1}(3/5) = 37^o$):

Material $A$ has a critical angle ${i_A},$ and material $B$ has a critical angle ${i_B}$ $({i_B} > {i_A})$. Then which of the following is true?
$(i)$ Light can be totally internally reflected when it passes from $B$ to $A$.
$(ii)$ Light can be totally internally reflected when it passes from $A$ to $B$.
$(iii)$ The critical angle for total internal reflection is ${i_B} - {i_A}$.
$(iv)$ The critical angle between $A$ and $B$ is ${\sin ^{ - 1}}\left( {\frac{{\sin {i_A}}}{{\sin {i_B}}}} \right)$.

$A$ point source $S$ is placed at the bottom of a transparent block of height $h = 10 \ mm$ and refractive index $n_B = 2.72$. It is immersed in a liquid of lower refractive index $n_L$ as shown in the figure. It is found that the light emerging from the block into the liquid forms a circular bright spot of diameter $D = 11.54 \ mm$ on the top surface of the block. The refractive index of the liquid $n_L$ is:

$A$ ray of laser of a wavelength $630 \, nm$ is incident at an angle of $30^{\circ}$ at the diamond-air interface. It is going from diamond to air. The refractive index of diamond is $2.42$ and that of air is $1$. Choose the correct option.

$A$ light ray is incident normally on one face of a right-angled prism and travels parallel to the base inside the prism. If the refractive index of the prism is $\mu$,what should be the angle $\alpha$ that the hypotenuse makes with the base so that the ray undergoes total internal reflection at the hypotenuse?

An optical fiber works on the principle of ......