width of central maximum?

Question

Light of wavelength 598 nm illuminates a single 0.77 mm wide slit. At what distance from the slit should a screen be placed if the first minimum in the diffraction pattern is to be 2.03 mm from the central maximum?

2.614 m, i got this right

What is the width of the central maximum?

no idea i cant seem to get this answer any suggestions...?

Answer 1

The full width of the central maximum is just twice the distance to the first minimum. See the ref.

Answer 2

just double the width of the image on the screen.

.77mm x 2 = 1.54mm for the total width of the central maximum

it has nothing to do with the calculation of part a