Useful number(s): c=3.00x108 m/s, h=6.626x10-34 J·s
1) A beam of electrons hits a double slit with separation 10nm and produces a 3rd 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?
2) A red LED (Light Emitting Diode) emits a 1Watt, 690nm wavelength light beam. The beam shines on a screen. How many photons hit the screen during a 1 second interval?