(a(i))[1]
No light refracts out of the fibre at points P and Q. State the name of the process that takes place at P and Q.
(a(ii))[2]
Calculate the minimum value of angle i for there to be no refraction at point P.
(b)[3]
State and explain how optical fibres are used in medicine.
(c)[2]
The ray of light shown in Fig. 7.1 is monochromatic light from a laser. State what is meant by monochromatic light. Use one of these quantities in your answer: amplitude, brightness, frequency, refractive index, speed.