The angle in radians, locating the m th fringe can be calculated by .

Where,

is the distance between the two slits.

is the wave length of the wire.

(a)

Consider .

Multiply each side by .

Divide each side by .

Apply reciprocal identity : .

.

Divide each side by .

.

(b)

Find the angle .

Wave length : nanometers.

The distance between the two slits millimeters.

Convert millimeters to nanometers.

.

Consider .

Substitute the values of , nm, and in above formula.

Thus, the angle is radians.

(a). .

(b). The angle is radians.