Just show work, no graphs needed. Due today 5/09/2013 2pm!

#1 Helium-neon laser light with the wavelength of 632.8 nm is sent through a 0.300-mm wide single slit.
 a) What is the width of the central maximum observed on the screen 1.50 m from the slit?
b) How far is the second dark band from the central maximum?

#2 Magnesium fluoride is used in photography to apply a thin film of coating onto lens surface of a
camera in order to minimize reflection The index of refraction of the lens is 1.60 while the covering
coating layer has the index of refraction of 1.38. If the coating layer helps to produce destructive
interference for the green light of 550 nm, find the minimum thickness of the coating layer.
b) how many phase reversals does occur in this case? Explain.

#3 What is the minimum frequency of the visible prominent lines emitted by hydrogen gas discharge?
(Determine using the Balmer series formula).

#4 A parallel beam of light from a He-Ne laser, with a wavelength of 656 nm falls on two slits
and produces an interference pattern in which the third order fringe is 32 mm from the central fringe
on a screen 1.6 m away. a) What is the separation of the two slits?
b) What is the width of the central bright band?

An oil film (n=1.45) floating on water (n = 1.33) is illuminated by white light an normal
 incidence. The film is 2.80×102 nm thick. Find a) the wavelength and color of the light in the
visible spectrum most strongly reflected and b) the wavelength and color of the light in the
visible spectrum most strongly transmitted.