This diagram is given in my textbook. There are 'partially reflected rays' when the 'angle of incidence' is less than 'critical angle'. But when the 'angle of incidence' is equal to 'critical angle', there are no 'partially reflected rays'. Is this correct?
I checked youtube for a real demonstration and found this video: https://www.youtube.com/watch?v=NAaHPRsveJk
It shows a 'partially reflected ray' even at critical angle, which then becomes the 'totally reflected ray' for higher incidence angles.