91Ó°ÊÓ

a) The reasoning for this is often that pattern on the screen is formed by interference and diffraction from individual single slits, and in some scenarios, an interference maximum occurs with just a diffraction pattern minimum, resulted during a missing order. The interference maximum rested exactly on the primary minimum within the focal plane within the case of the scholar, therefore the predicted sharp fringes during this position isn't seen.

We indicated in portion (a) that the m=5 interference maximum coincides with the first minimum in the diffraction pattern, implying that they are both the same distance from the Centre maximum. As a result, for the diffraction pattern's first dark fringe.

$y_p=\frac{p\mathrm{λ}L}{a}p=1,2,3,…$

$y_1=\frac{\mathrm{λ}L}{a}$

$a=\frac{\mathrm{λ}L}{y_1}=\frac{\left(1.5\mathrm{m}\right)×\left(530×{10}^{−9}\mathrm{m}\right)}{1.6×{10}^{−2}\mathrm{m}}=4.97×{10}^{−5}\mathrm{m}$

$a=50\mathrm{μ}\mathrm{m}$