The refractive index of water is $4/3$ and that of glass is $5/3$. What will be the critical angle for a ray of light entering water from glass?

The graph between the sine of the angle of refraction $(\sin r)$ in medium $2$ and the sine of the angle of incidence $(\sin i)$ in medium $1$ is shown below. Based on this,which of the following statements is correct? (Given: $\tan 36^o \approx \frac{3}{4}$)

$A$ planar structure of length $L$ and width $W$ is made of two different optical media of refractive indices $n_1=1.5$ and $n_2=1.44$ as shown in the figure. If $L \gg W$,a ray entering from end $AB$ will emerge from end $CD$ only if the total internal reflection condition is met inside the structure. For $L = 9.6 \ m$,if the incident angle $\theta$ is varied,the maximum time taken by a ray to exit the plane $CD$ is $t \times 10^{-9} \ s$,where $t$ is. . . . . . . [Speed of light $c = 3 \times 10^8 \ m/s$]

The relation between the critical angles of water and glass is:

$A$ light ray is incident from a denser medium to a rarer medium at an angle of incidence $i$. If the reflected and refracted rays are mutually perpendicular,then the critical angle for the interface is:

At what angle of incidence should a ray be incident on a glass sphere of refractive index $3/2$ so that the ray does not emerge from the sphere?