Draw a graph to show the variation of the angle of deviation $$ ( \delta ) $$ with that the angle of incidence (i) for a monochromatic ray of light passing through a glass prism of refracting angle 'A' then deduce the relation:
$$ \mu =\frac { sin\left( \frac { A+S_ m }{ 2 } \right) }{ sin\frac { A }{ 2 } } $$