Topic Cluster

Modern Physics

Relativity, quantum mechanics, and the strange truths discovered when we looked closely enough at the universe.

De Broglie Wavelength: Formula, Examples and Worked Problems

Every moving particle has a wavelength given by the de Broglie equation. This guide covers the formula, the electron voltage shortcut, six real examples and eight fully worked problems.

14 min read

Modern Physics

Time Dilation: Formula, Twin Paradox and Real Experiments

Time dilation is the difference in elapsed time between two clocks caused by relative motion or gravity. This guide covers the formula, the twin paradox, worked examples and the real experiments that measured it.

16 min read

Modern Physics

Photon Energy Formula (E = hf): Explained

The photon energy formula E = hf links a photon's energy to the frequency of its light. See both forms of the equation, real examples from radio to gamma rays, and eight fully worked problems.

13 min read

Modern Physics

E=mc² Explained: What Einstein’s Formula Really Means

E=mc² explained in plain English: what Einstein's famous formula means, why mass and energy are the same thing, and worked examples showing the huge energy locked inside even a single gram of matter.

12 min read

Modern Physics

Radioactivity: Alpha, Beta & Gamma

Alpha, beta and gamma radiation compared: what each type is, what stops it, how the decay equations work — and why the least penetrating type is the most dangerous inside the body.

14 min read

Modern Physics

Photoelectric Effect Explained

How light ejects electrons from metals: Einstein's photoelectric equation, threshold frequency, work functions, worked problems and real-world uses of the photoelectric effect.

14 min read

Modern Physics

What Is Half-Life in Physics?

Half-life is the time for half a radioactive sample to decay. This guide explains the half-life formula, the decay constant, worked examples and how carbon dating works.

12 min read

Modern Physics

The Speed of Light Explained

The speed of light (c) is exactly 299,792,458 m/s — the fastest anything can travel and the universe's ultimate speed limit. Here's what that means, why it's constant, and how to work with it.

13 min read

Modern Physics

What Is Special Relativity?

Special relativity explains how time, length and energy change near the speed of light. Master Einstein's two postulates, the key formulas and the twin paradox — with worked examples.

16 min read