Question

If a beam of white light in air strikes a sheet of this glass at 66.0 ∘∘ with the normal in air, what will be the angle of dispersion between the extremes of visible light in the glass? In other words, what will be the angle between extreme red and extreme violet light in the glass?

Answer 1

Answer:

The angle between the extreme red and extreme violet light in the glass is 1.18°

Explanation:

According the Snell's law:

$n_{a} sin\theta _{a} =n_{b} sin\theta _{b}\\\theta _{b} =sin^{-1} (\frac{n_{a}sin\theta a}{n_{b} } )$

Where

na = refractive index of air = 1

θa = angle of incidence in air = 66°

For red light nb = 1.61

Replacing:

$\theta _{b} =sin^{-1} (\frac{1*sin66}{1.61} )=34.57$

For violet light nb = 1.66

$\theta _{b} =sin^{-1} (\frac{1*sin66}{1.66} )=33.39$

So, the angle between the extreme red and extreme violet light in the glass is 34.57-33.39 = 1.18°