Condition for maximum:

$\overline{){\mathbf{d}}{\mathbf{}}{\mathbf{s}}{\mathbf{i}}{\mathbf{n}}{\mathbf{}}{\mathbf{\theta}}{\mathbf{=}}{\mathbf{m}}{\mathbf{\lambda}}}$

For maximum, m = 1

Since the angle between the interference patterns is very small, we can make the approximation:

θ = λ/d

1 μm = 1000 nm

**(a) **θ = (450 × 10^{-3})/400 = **1.1 × 10 ^{-3} rad**

Four trials of Young's double-slit experiment are conducted.

(a) In the first trial, blue light passes through two fine slits400 μm apart and forms an interference pattern on a screen 4 m away.

(b) In a second trial, red light passes through the same slits and falls on the same screen.

(c) A third trial is performed with red light and the same screen, but with slits 800 μmapart.

(d) A final trial is performed with red light, slits 800μm apart, and a screen 8 m away.

Rank the trials (a) through (d) from largest to smallest value of the angle between the central maximum and the first-order side maximum. In your ranking, note any cases of equality.