1) In converting electrical energy into light energy, asixty-watt incandescent light bulb operates at about 2.2% efficiency. Assuming that all of the light is greenlight (wavelength approximately 5500 Å), determine the number of photons per second given offby the bulb.
2) Continuing with the example in question 1 – if you were tolook directly at the bulb, the light from it would travel directly to your eye without reflecting fromanything. If you stand 3.5 meters away and look at the bulb for only 0.10 seconds, how manyphotons will enter your eye? (assume the pupil of your eye has a diameter of 2.1 mm) So is it a good idea to look directly at the bulb (or even througha filter) when it’s on?
3) You are given a silver surface and you know that the workfunction (W0 or Φ) for silver is 4.73 eV. Find the minimum frequency (cutoff frequency f0) that lightmust have to eject electrons from this surface.
What is the maximum wavelength that will cause electrons to beejected?