Answer
$\phi = 29.0^{\circ}$
Work Step by Step
We can use Equation (33-45) to find the critical angle $\theta_c$:
$\theta_c = sin^{-1}~\frac{n_2}{n_1}$
$\theta_c = sin^{-1}~\frac{1.33}{1.52}$
$\theta_c = 61.0^{\circ}$
For total reflection, the minimum incident angle of the light is $61.0^{\circ}$
By geometry, the incident angle is $90^{\circ}-\phi$
We can find the maximum angle for $\phi$:
$\phi = 90^{\circ}-61.0^{\circ} = 29.0^{\circ}$
