1) A ray of light travelling through rarer medium is incident at very small angle i on a glass slab and after refraction, its velocity is reduced by 20%. The angle of deviation is A) $\frac{i}{8}$ B) $\frac{i}{5}$ C) $\frac{i}{2}$ D) $\frac{4i}{5}$ Answer: Option BExplanation:According to question , at glass-air interface velocity is reduced by 20% of the velocity of light So, deviation $\delta$ =20% of i = $\frac{20\times i}{100}=\frac{i}{5}$
