# Physics II For Dummies

From Physics II For Dummies by Steven Holzner

Here’s a list of some of the most important equations in Physics II courses. You can use these physics formulas as a quick reference for when you’re solving problems in electricity and magnetism, light waves and optics, special relativity, and modern physics.

## Physics Equations for Electricity and Magnetism

Electricity and magnetism make up one of the most successful fields of study in physics. When working mathematically with electricity and magnetism, you can figure out the force between electric charges, the magnetic field from wires, and more. Keep the following equations handy as you study these topics:

## Light Wave and Optics Formulas

Light waves — that is, electromagnetic waves — behave like other waves: They can reflect, refract (bend), and interfere with each other. Here are some wave formulas that are useful when you’re working with optics. You can determine the wave frequency and period, predict how fast light travels in various materials, and determine how light will bend in lenses and bounce off mirrors.

## Formulas from Einstein’s Theory of Special Relativity

Einstein’s theory of special relativity describes what happens as things near the speed of light. Here are some important special-relativity equations that deal with time dilation, length contraction, and more.

## Quantum Mechanics and Other Modern Physics Topics

Modern physics includes all sorts of topics, such as quantum mechanics, matter waves, radioactivity, the spectrum of hydrogen, and more.