Dose E=hn means quantization of energy?

  1. I have an example class yesterday, but one question troubled me.

    In part (b), why does E=nhf?
    For me, it seems E=nh is enough, why does the equation involve frequency f after quantization?

    Attached Files:

  2. jcsd
  3. One answer might be: The unit of E (energy) is a Joule, the unit of h (Plank's constant) is Joule time a second. If you want the equation to be correct you need to multiply h with something that has units of 1 over a second.

  4. What do you mean "E = nh is enough"? That equation is not correct, because as pointed out above, the units are not correct.
  5. h = energy per cycle.
    f = number of cycles per unit of time.
    your quantization must include a quantization of time.
  6. Thanks! I have forgotten to consider the unit.
  7. Energy within a single system is quantized, but there are different energies that result from following the E=nh model in different systems, so if you consider every possible system energy is continuous, just like the light spectrum.
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