Energy is emitted or absorbed in discrete packets called quanta, with E equal to h times frequency.
Practise Atomic Structure & Periodicity All Atomic Structure & Periodicity topics
Max Planck proposed in 1900 that the energy of an oscillator is quantized, exchanged only in discrete packets with energy E = h x nu, where h = 6.626 x 10^-34 J s is Planck's constant. This means energy is not continuous at the atomic scale, a radical departure from classical physics. The idea explained the shape of black body spectra completely. Einstein extended it to light in 1905 to explain the photoelectric effect, and Bohr applied it to atomic spectra. Planck's constant is one of the fundamental constants of nature.
Key ideas: Energy is emitted or absorbed in packets: E = n h nu with h = 6.626 x 10^-34 J s and n a whole number. So energy is quantized, not continuous. For a single photon E = h c / lambda; per mole multiply by N_A. At 500 nm, E = 3.97 x 10^-19 J, which is about 239 kJ per mol.
Common mistakes and connections: Students forget that n is an integer, or use h in the wrong units (J s versus eV s, 4.136 x 10^-15). Energy quantization applies to atomic scale; at macro scale steps are unobservably small. It leads directly to Einstein's photon and Bohr's atom.
At a cooler 3000 K the peak shifts to infrared and the total emission drops, as predicted by energy quantized in packets of h times frequency. The interactive lesson shows this as a live animation or chart.
A 500 nm photon has E = (6.626 x 10^-34)(6.0 x 10^14) = 4.0 x 10^-19 J.
Energy is emitted or absorbed in discrete packets called quanta, with E equal to h times frequency.
Planck's Quantum Theory is a intermediate topic in Atomic Structure & Periodicity. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Atomic Structure & Periodicity first: Wavelength and Frequency, Electromagnetic Spectrum, Black Body Radiation.
The next topics in Atomic Structure & Periodicity are Photoelectric Effect and Threshold Frequency.
Yes. The interactive lesson includes a self-check question on Planck's Quantum Theory, and the Atomic Structure & Periodicity quiz draws on every topic in this area.
Planck's Quantum Theory is topic 36 of 115 in Atomic Structure & Periodicity.