How far the first bright diffraction fringe is from the strong central maximum if the screen is 12.0 m away. Express your answer to three significant figures and include the appropriate units.

The distance of any bright fringe from the central maximum on the screen in a single slit diffraction is given by,

Ym = (2m + 1) lL/2a

where m = 1

l = wave length,

L = width of the slit

a = distance from the centre of the slit

m = 1, l = 640 x 10-9nm, L = 3.4 x 10 - 3 and a = 12m.

Ym = (2x1 + 1) 640 x 10-9 x 3.4 x 10-3 / 2 x 12

= 2.72 x 10-9m