Useful number(s): c=3.00x108 m/s, h=6.626x10-34 J·s
1) A 126nm thick film of oil (n=1.38) is sitting on top of a glass plate (n=1.53). What is the largest wavelength of light (in air) that will destructively interfere? What color will the surface appear?
2) 680nm light illuminates a 2300 line-per-cm diffraction grating and produces its 2nd order maximum a distance y above the central maximum on a screen, which is 1m away from the grating. What is y?
3) A beam of electrons hits a double slit with separation 0.2nm and produces a 1st order minimum 1μm above the central maximum on a screen which is a distance 100m away from the slit. What is the momentum of the electrons?
4) A red LED (Light Emitting Diode) emits a 2Watt, 720nm wavelength light beam. The beam shines on a screen. How many photons hit the screen during a 2 second interval?