Critical angle will be maximum, when light travels from

The critical angle between two media is given by $i_{c}=\sin ^{-1}\left(\frac{\mu_{1}}{\mu_{2}}\right)$ As we know that, $\mu_{\text {air }}=1, \mu_{\text {water }}=1.33, \mu_{\text {glass }}=1.5$ and $\mu_{\text {diamond }}=2.4$. From given values, $\frac{\mu_{1}}{\mu_{2}}$ is maximum for water-glass interface. So, critical angle will also be maximum, when light travels from glass to water.