(a) (i) Define Optical angle.

(ii) Explain two conditions necessary for total internal reflection to occur. 

(iii) List three practical applications of total internal reflection.

(b) State two effects of refraction. 

(c)(i) Define progressive waves.

(ii) A plane progressive wave is represented by the equation y = 0.5 sin(1000\(\pi\)r = \(\frac{100 \pi \lambda}{17}\)) where y is in millimetres, t in seconds and x in metres.  Calculate the: (\(\alpha\)) frequency of the wave; (\(\beta\))of the wave; (\(\gamma\)) speed of the wave