Advanced Quantum Physics Mastery

Einstein's Nobel Prize wasn't for relativity. It was for this.

In 1905 he explained why dim blue light can knock electrons out of a metal while bright red light can't: light comes in packets, photons, and only their individual energy matters. Twenty questions on the physics of the very small, each explained, then try it yourself. No sign-up, nothing saved.

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QUESTION 1 / 20 · QUANTA & PHOTONSMedium

Who first proposed, in 1900, that energy is emitted in discrete packets?

PHOTOELECTRIC LAB

Which colours of light can free an electron?

Each metal holds its electrons with a certain energy, its work function. A photon must carry at least that much on its own. Change the wavelength and brightness, then switch metals.

200 nm · UVthreshold 539 nm700 nm · red

Wavelength450 nm · blueBrightness (photons per second)5 / 10

2.76 eVphoton energy

2.3 eVwork function

0.46 eVmax electron KE

Each photon has 2.76 eV, more than the 2.3 eV work function, so electrons escape with up to 0.46 eV. Brightness changes how many escape, not how fast.

Photon energy E = hc / λ ≈ 1240 / λ(nm) electronvolts. Maximum kinetic energy of an ejected electron = E − φ. Work functions are typical values; they vary with surface condition.

What this quantum physics test covers, in short

Twenty multiple-choice questions at first-year university level, four on each of five topics: quanta and photons, wave–particle duality, atoms and spectra, uncertainty and measurement, and quantum technology. Most questions test concepts rather than heavy maths.

Interpretations of quantum mechanics are still debated; questions stick to what experiments show. The test is our own and not normed.

By What's Your IQ · Reviewed 5 Oct 2026

Format: 20 multiple-choice questions
Level: First-year university
Bonus: Photoelectric-effect lab with 4 metals
Key constant: Planck's constant h ≈ 6.63 × 10⁻³⁴ J·s

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Einstein's Nobel Prize wasn't for relativity. It was for this.

Who first proposed, in 1900, that energy is emitted in discrete packets?

Which colours of light can free an electron?

What this quantum physics test covers, in short

Keep going

Quantum ideas defy intuition. How flexible is your thinking?