A prism has refracting angle of `60°` and its material has refractive index 1.5 and 1.6 for red and violet light respectively. A parallel beam of white light is incident on one face of the prism such that the red light undergoes minimum deviation. Find the angle of incidence (i) and the angular width `(theta)` of the spectrum obtained.
Given: `sin (49^(@)) = 0.75^(@), sin(28^(@)) = 0.47, sin(32^(@)) = 0.53, sin(58^(@)) = 0.85`