b
\(\,sin\,\,\theta \,\, = \,\,\frac{\lambda }{a}\,\,\,\,\theta \,\, = \)  મધ્યસ્થ અધિકતમ ની કોણીય પહોળાઈ

\(a\,\, = \,\,12\,\,\, \times \,\,1{0^{ - 5}}\,\,cm,\,\,\lambda \,\, = \,\,6000\,\,\mathop A\limits^ \circ  \,\,\, = \,\,6\,\, \times \,\,{10^{ - 5}}\,\,cm\,\,\,\,\)

\(\therefore \,\,\,\sin \,\,\theta \,\, = \,\,\,\frac{\lambda }{a}\,\, = \,\,\,\frac{{6\,\, \times \,\,{{10}^{ - 5}}}}{{12\,\, \times \,\,{{10}^{ - 5}}}}\,\, = \,\,0.50\,\,\,\, \Rightarrow \,\,\theta \,\, = \,\,{30^ \circ }\)