Q 9.17 (b) What is the answer if there is no outer covering of the pipe?
In the case when there is no outer layer,
Snell's law at glass-air interface(when the ray is emerging out from the pipe)
36.5
refractive angle corresponding to this = 90 - 36.5 = 53.5.
the angle r is greater than the critical angle
So for all of the incident angles, the rays will get total internally reflected.in other words, rays won't bend in air-glass interference, it would rather hit the glass-air interference and get reflected