Energy that travels as oscillating electric and magnetic fields at the speed of light in vacuum.
Practise Atomic Structure & Periodicity All Atomic Structure & Periodicity topics
Electromagnetic radiation consists of oscillating electric and magnetic fields that are perpendicular to each other and to the direction of travel. In a vacuum it travels at the speed of light, c = 3.00 x 10^8 m/s, and it includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays. It behaves as a wave with a defined wavelength and frequency, and as a stream of photons when it exchanges energy with matter. Its interaction with atoms and molecules provides most of what we know about atomic structure. Spectroscopy uses these interactions to identify substances.
Key ideas: Light is an oscillating electric and magnetic field travelling at c = 3.00 x 10^8 m per s in vacuum, with the fields perpendicular to each other and to the direction of travel. All EM waves obey c = wavelength x frequency. It can behave as a wave (diffraction, interference) and as particles (photons), and needs no medium.
Common mistakes and connections: Students think sound and light are the same kind of wave; sound is a mechanical wave needing a medium and travels at about 340 m per s. EM radiation speed changes in a medium (n = c / v) while frequency does not. This topic leads to the spectrum, quantum theory and spectroscopy.
Light is a transverse wave of oscillating electric and magnetic fields; the distance between crests is its wavelength. The interactive lesson shows this as a live animation or chart.
A microwave oven uses radiation near 2.45 GHz, which is absorbed efficiently by water molecules and heats the food.
Energy that travels as oscillating electric and magnetic fields at the speed of light in vacuum.
Electromagnetic Radiation 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: Mass Spectrometry, Cathode Rays, Millikan's Oil Drop Experiment.
The next topics in Atomic Structure & Periodicity are Wavelength and Frequency and Electromagnetic Spectrum.
Yes. The interactive lesson includes a self-check question on Electromagnetic Radiation, and the Atomic Structure & Periodicity quiz draws on every topic in this area.
Electromagnetic Radiation is topic 32 of 115 in Atomic Structure & Periodicity.