Light and the electromagnetic spectrum Study Guide

Electromagnetic (EM) waves are a fundamental aspect of physics, encompassing a broad spectrum from radio waves to gamma rays. A key characteristic common to all EM waves is their transverse nature. This means that the oscillations of the electric and magnetic fields, which constitute the wave, are perpendicular to the direction in which the wave is travelling. Furthermore, all electromagnetic waves share an identical speed when propagating through a vacuum, often denoted as 'c'. This constant speed is approximately 3.0 x 10^8 meters per second, a value universally consistent across the entire electromagnetic spectrum.

Changes within atoms and atomic nuclei are fundamental processes in physics that can both generate and be caused by electromagnetic radiation. When electrons within an atom move from a higher energy level to a lower one, or when atomic nuclei undergo decay or fusion, they emit energy in the form of electromagnetic radiation. This radiation can span a broad spectrum of frequencies, including visible light, X-rays, and gamma rays, depending on the energy involved in the transition. Conversely, atoms and nuclei can absorb electromagnetic radiation. When an atom absorbs a photon with sufficient energy, an electron can jump to a higher energy level. When a nucleus absorbs a high-energy photon or particle, it can become unstable, potentially leading to nuclear reactions or changes in its state.