Explanation:
The circuit wouldn't work because if you remove 1 light bulb all of them will stop working because they're all conected
The critical angle is the angle of incident in the optically dense media that produces the angle of refraction as 90°.
sin c =1/n, where n is the refractive index and c is the critical angle.
Also, n1sinФ1=n2sinФ2
In this case we have,
1.33×sinc = 1.309×sin90° Where c is the critical angle.
sin c =1.309/1.33
sin c = 0.981995498
c = 79.11°