The critical angle of light passing from glass to air is minimum for which wavelength?

The wavelength of light in two liquids $x$ and $y$ is $3500 \ \mathring{A}$ and $7000 \ \mathring{A}$ respectively. The critical angle of $x$ relative to $y$ will be.......$^o$

For a light ray to undergo total internal reflection, light must travel from $(i = \text{angle of incidence}, i_C = \text{critical angle})$

$A$ glass prism of refractive index $1.5$ is immersed in water (refractive index $\frac{4}{3}$) as shown in the figure. $A$ light beam incident normally on the face $AB$ is totally internally reflected at the face $AC$ to reach the face $BC$,if:

An endoscope is employed by a physician to view the internal parts of a body organ. It is based on the principle of

$A$ glass prism of refractive index $1.5$ is immersed in water (refractive index $4/3$) as shown in the figure. $A$ light beam incident normally on face $AB$ undergoes total internal reflection at face $BC$.