In the double-slit experiment of figure a below, monochromatic orange light of w
ID: 1697740 • Letter: I
Question
In the double-slit experiment of figure a below, monochromatic orange light of wavelength 600 nm illuminates the two parallel narrow slits S1 and S2. The slits are d = 7.50 µm apart. Waves from the slits (which extend into and out of the page) combine at P, an arbitrary point on screen C at distance y from the central axis. The angle serves as a convenient locator for P. For D d, we can approximate rays r1 and r2 as being parallel, at angle to the central axis (figure b).
(a) Calculate the angular deviation of the third-order (for m = 3) bright fringe in radians.
1 rad
(b) What is this value in degrees?
2°
Explanation / Answer
The given wave length = 600nm
the seperation between the slits d = 7.50m
Then the condition for bright fringes
dsin = m
therefore the deviation
sin = m/d = (3)(600*10^-9)/(7.50*10^-6)
= 0.2423 rad
then = 13.88 deg