Final answer:
A quantum of energy is the minimum quantity of energy that can be either lost or gained by an atom, calculated as E = hf, where E is energy, h is Planck's constant, and f is frequency.
Step-by-step explanation:
A quantum of energy is the minimum quantity of energy that can be lost or gained by an atom. When Max Planck was analyzing the spectra of blackbody radiation, he found that energy was not emitted continuously but in discrete units called quanta. The amount of radiant energy absorbed or emitted by an object is directly proportional to the frequency of the radiation and can be calculated using the formula E = hf, where E is the energy, h is Planck's constant (h = 6.626 × 10-34 J·s), and f is the frequency of the radiation.
This concept led to the understanding of light as having a dual nature, known as wave-particle duality, where it can behave as both a wave and a particle (photon). Thus, each photon of light carries a specific quantum of energy, which depends on its frequency.