Light of Wavelength 420 Nm Is Incident on a Slit

Multiple Choice

Light of wavelength 420 nm is incident on a slit of width 0.20 mm,and a diffraction pattern is produced on a screen that is 1.80 m from the slit.What is the width of the central bright fringe? (1 nm = 10−⁹ m)

A) 3.8E-3 m
B) 7.6E-3 m
C) 1.2E-3 m
D) 1.4E-2 m
E) 2.0E-2 m