A double slit has two slits of width 0.650 mm separated by a distance between centers of 2.340 cm. With a mercury arc as a source of light, the green line at A = 5460.74 A is used to observe the Fraunhofer diffraction pattern 100 em behind the slits. (a) Assuming the eye can resolve fringes that subtend 1minute of arc, what magnification would be required to just resolve the fringes? (b) How many fringes could be seen under the central maximum? (c) How many under the first side maximum?

Solve part A using the following formulas

SIn(theta)=(y/25)

magnification= (1 minute arc)/(theta in minutes)

1 degree = 60minutes

Ans. (a) 3.1x, (b) 71 fringes, (c) 35 fringes