K.C.S.E Physics Q & A - MODEL 1998PP2QN05

K.C.S.E Physics Q & A - MODEL 1998PP2QN05

a) A ray of white light is incident on one face of a rectangular glass prism.
i) Draw a ray diagram to illustrate the dispersion of white light by the prism, showing only the red ® and violet (V) rays.
ii) On the same diagram drawn in (i) mark and label the initial angle of incidence, 1, and the angles of reflection on the first face for red rR and for violet rV.
iii) Snell's law for the red and colours can be written as
nr= Sin I/Sin  rR 

b) Calculate the critical angle for a material whose refractive index is 1.40.

ANSWERS