Which of the following statements are true concerning Planck's quantum hypothesis?
Check all that apply.
1. An upper limit is set on the amount of energy that can be absorbed or emitted in oscillations.
2. A lower limit is set on the amount of energy that can be absorbed or emitted in oscillations.
3. The energy of the oscillations of atoms within molecules can have any value.
4. The energy of the oscillations of atoms within molecules must be quantized.