In a single slit experiment a wave of wavelength $0.2 \;cm$ is incident normally on a slit of width $0.004\;m$ . What is the semi angular width of the central maxima.

Question

$(a)\;60^{\circ} \\ (b)\;30^{\circ} \\ (c)\;15^{\circ} \\ (d)\;0^{\circ}$