Planck's quantum theory proposed that energy is emitted or absorbed

  • A. continuously in any amount
  • B. in discrete packets called quanta, each of energy hf
  • C. only as heat
  • D. only by solids

Explanation

Planck found that black body radiation could only be explained if the energy came in multiples of hf, where h is Planck's constant and f the frequency. Classical physics assumed a continuous exchange and predicted infinite energy at short wavelengths, the so called ultraviolet catastrophe. Quantisation resolved that failure and began quantum physics.

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