Answer to Question #48907 in Electricity and Magnetism for Gay Awado

Question

. Basic wave theory predicted that a blackbody should put out more energy at higher frequencies. In reality, above the peak frequency a real blackbody emits less radiation with increasing frequency. Planck was able to explain this contradiction by assuming that light energy is quantized and that higher frequencies of light have a bigger quantum. Explain why light energy being quantized this way means that a blackbody will emit less energy at higher frequencies.





2. The photoelectric effect is the name given to the process where light waves striking the surface of a metal frees some electrons and produces an electric current. How is it possible for a light wave to liberate an electron from a piece of metal?




3. If all electromagnetic waves are made up of photons (discrete quanta), why don’t we hear the effect of each distinct packet of energy when we listen to a radio (which is being effected by a radio wave)?




4. For biological organisms, more damage is done to cells by standing in front of a very weak (low power) beam of x-rays than in front of a much brighter red light. How does the photon concept explain this situation that an 18th century physicist would have found paradoxical?





5. In photoelectric effect experiments, no photoelectrons are produced when the frequency of the incident radiation drops below a cutoff value (which varies depending on the metal used in the experiment), no matter how bright or intense the light is. How can you explain this fact using a “particle” theory of light instead of a wave theory of light?






6. What is the energy of one quantum of 5.0 x 1014 Hz light?


7. A photon has 3.3 x 10-19 J of energy. What is the wavelength of this photon? What part of electromagnetic spectrum does it come from?