c
અર્ધ કોણીય પહોળાઈ \( = \,\,\,\frac{\lambda }{d}\,\, = \,\,\frac{{6000\,\, \times \,\,{{10}^{ - 10}}}}{{12\,\, \times \,\,{{10}^{ - 5}} \times \,\,{{10}^{ - 2}}}}\,\,\, = \,\,\frac{1}{2}\)
\( = \,\,\,\frac{1}{2}\,\, \times \,\,\,\frac{{180}}{\pi }\,\, = \,\,{30^ \circ }\)