Physics Question from JEE Main 2023 · 29 January, Shift 2

Unpolarised light is incident on the boundary between two dielectric media whose dielectric constants are $2.8$ (medium $1$) and $6.8$ (medium $2$) respectively. For the reflected and refracted rays to be perpendicular to each other, the angle of incidence should be $\tan^{-1}\left(1 + \dfrac{10}{\theta}\right)^{\frac{1}{2}}$. The value of $\theta$ is:

(Given, for the dielectric media, $\mu_r = 1$)