Name:______________________

Name:_______________________

Quiz 10

05/23/2006

Ch. 27,29

Useful number(s): c=3.00x10⁸m/s, h=6.626x10^-34J·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 2^nd 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 1^st 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?