173- A light ray passes through a prism following the path shown in the figure below. Which answer is not correct?
[(1)] The refractive index of the prism is $\sqrt{2}$.
[(2)] The deviation angle of the light ray is $135°$.
[(3)] The critical angle of the prism with respect to air is $45°$.
[(4)] The speed of light in the prism is $\dfrac{\sqrt{2}}{2}$ times the speed of light in air.
[Figure: A prism with a light ray entering and refracting, with an angle of $135°$ marked]
\textbf{173-} A light ray passes through a prism following the path shown in the figure below. Which answer is \underline{not} correct?
\begin{itemize}
\item[(1)] The refractive index of the prism is $\sqrt{2}$.
\item[(2)] The deviation angle of the light ray is $135°$.
\item[(3)] The critical angle of the prism with respect to air is $45°$.
\item[(4)] The speed of light in the prism is $\dfrac{\sqrt{2}}{2}$ times the speed of light in air.
\end{itemize}
\textit{[Figure: A prism with a light ray entering and refracting, with an angle of $135°$ marked]}