We have to combine a crown glass prism of angle `4^(@)` with a flint glass prism in such a way that the mean ray passes undeviated, find (i) the angle of the flint glass prism needed and (i) the angular dispersion produced by the combination when white light goes through it. Refractive indices for red, yellow and violet light are 1.514, 1.517 and 1.523 respectively for crown glass and 1.613, 1.620 and 1.632 for flint glass.

Explanation

To solve the problem, we need to find the angle of the flint glass prism required to ensure that the mean ray passes undeviated, and then calculate the angular dispersion produced by the combination when white light passes through it.

### Step 1: Understanding the Condition for No Deviation
For the mean ray to pass undeviated through the combination of prisms, the following condition must be satisfied:
\[ (\mu_y - 1) A = (\mu'_y - 1) A' \]
where:
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