https://www.khanacademy.org/science/ms-physics/x1baed5db7c1bb50b:waves/x1baed5db7c1bb50b:electromagnetic-waves/v/the-electromagnetic-spectrum 2025-07-01T10:10:08.145512912Z The electromagnetic spectrum Light is an electromagnetic wave. All electromagnetic waves travel at the speed of light in vacuum. The frequency of a light wave corresponds to its color. The amplitude of a light wave corresponds to its brightness. Visible light is only a small part of the electromagnetic spectrum, which also includes radio, microwaves, infrared, ultraviolet, X-rays, and gamma rays. These different frequencies of electromagnetic waves have different applications. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/e317d099-29e7-41b4-a05c-8f7178545f8b_1280_720_base.png The electromagnetic spectrum Light is an electromagnetic wave. All electromagnetic waves travel at the speed of light in vacuum. The frequency of a light wave corresponds to its color. The amplitude of a light wave corresponds to its brightness. Visible light is only a small part of the electromagnetic spectrum, which also includes radio, microwaves, infrared, ultraviolet, X-rays, and gamma rays. These different frequencies of electromagnetic waves have different applications. https://cdn.kastatic.org/ka-youtube-converted/iVbuCROYAz4.mp4/iVbuCROYAz4.mp4 523 Electromagnetic waves https://www.khanacademy.org/science/cosmology-and-astronomy/universe-scale-topic/light-fundamental-forces/v/introduction-to-light 2021-01-04T18:35:18Z Introduction to light Light and the electromagnetic radiation spectrum. Wave and particle-like behavior, and how to calculate the wavelength or frequency of a light wave.  Sal Khan video https://cdn.kastatic.org/googleusercontent/cVlKcFz4C0EyjX_DkTGccu23EagJYwwMVWw-oBtmT-CtU9iW8r-KoUvwu9HF_eYB3fgDOp3ER_z2r_umYyjl4xc Introduction to light Light and the electromagnetic radiation spectrum. Wave and particle-like behavior, and how to calculate the wavelength or frequency of a light wave.  https://cdn.kastatic.org/ka-youtube-converted/rLNM8zI4Q_M.mp4/rLNM8zI4Q_M.mp4 577 Electromagnetic waves https://www.khanacademy.org/science/highschool-physics/x6679aa2c65c01e53:electromagnetic-radiation/x6679aa2c65c01e53:wave-behaviors-of-em-radiation/v/electromagnetic_waves 2024-05-16T01:13:56.718395588Z Electromagnetic waves Electromagnetic (EM) waves are produced whenever electrons or other charged particles accelerate. The wavelength of an EM wave is the distance between consecutive points on the wave with the same phase (e.g. one crest to the next crest). The frequency of an EM wave is how many wave cycles are emitted, or pass a given point, per second. The speed of a wave is equal to its frequency times its wavelength. In vacuum, all EM waves travel at speed c = 3 x 10^8 m/s. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/fa27a4a6-9f11-4533-8d14-5569e37dfdff_1280_720_base.png Electromagnetic waves Electromagnetic (EM) waves are produced whenever electrons or other charged particles accelerate. The wavelength of an EM wave is the distance between consecutive points on the wave with the same phase (e.g. one crest to the next crest). The frequency of an EM wave is how many wave cycles are emitted, or pass a given point, per second. The speed of a wave is equal to its frequency times its wavelength. In vacuum, all EM waves travel at speed c = 3 x 10^8 m/s. https://cdn.kastatic.org/ka-youtube-converted/Je_f4RimfKI.mp4/Je_f4RimfKI.mp4 853 Electromagnetic waves https://www.khanacademy.org/science/in-in-class-12th-physics-india/in-in-electromagnetic-waves/in-in-phy-cbse-introduction-to-electromagnetic-waves/a/light-and-the-electromagnetic-spectrum 2021-07-06T13:18:37Z Light: Electromagnetic waves, the electromagnetic spectrum and photons Properties of electromagnetic radiation and photons article https://www.khanacademy.org/science/grade-7-science-snc-aligned/x64f379bc07a3640a:waves-and-energy/x64f379bc07a3640a:electromagnetic-waves/v/electromagneticspectrum 2020-06-23T07:22:43Z The electromagnetic spectrum The Sun is constantly broadcasting information about its activity in the form of light waves. Find out why there’s more to see than what meets the eye… NOVA video https://cdn.kastatic.org/googleusercontent/4sTEr0PfvBn596-d-w7g0wbUoc_dK1a00n0xvE-L-Xc0srCI7DPdZ12Gmc3nDBH4Fn8ZCfmjvyo72o4JcB5_kNGf The electromagnetic spectrum The Sun is constantly broadcasting information about its activity in the form of light waves. Find out why there’s more to see than what meets the eye… https://cdn.kastatic.org/ka-youtube-converted/m7c4-EO7ECE.mp4/m7c4-EO7ECE.mp4 177 Electromagnetic waves https://www.khanacademy.org/science/ms-physics/x1baed5db7c1bb50b:waves/x1baed5db7c1bb50b:electromagnetic-waves/a/electromagnetic-waves 2026-04-29T10:50:35.589391704Z Learn and try: Electromagnetic waves Learn about electromagnetic waves, including visible light waves. Explore the ray model and use it to model different behaviors of light. article https://www.khanacademy.org/science/teacher-resources-ngss-science-domain/x2811526c37de0eab:hands-on-science-activities/x2811526c37de0eab:high-school-physics-activities/a/activity-why-do-optical-discs-reflect-rainbow-colors 2026-01-08T00:49:44.500630731Z Activity: Why do optical discs reflect rainbow colors? Make science come alive in your classroom with this free hands-on activity aligned to high school standards. article https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:atomic-models-and-periodicity/x2613d8165d88df5e:the-bohr-model-and-atomic-spectra/e/apply-the-electromagnetic-spectrum 2026-04-26T16:30:39.382257956Z Apply: The electromagnetic spectrum Apply your knowledge of the electromagnetic spectrum in this set of free practice questions. Emily Cizmas exercise https://www.khanacademy.org/science/grade-10-physics-snc-aligned/x502b86fa259f0088:electromagnetic-spectrum/x502b86fa259f0088:why-is-the-sky-blue/v/why-is-the-sky-blue-ur 2025-08-08T00:24:37.843818748Z Why is the sky blue? Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Why is the sky blue? Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/vETlrH-Xguk.mp4/vETlrH-Xguk.mp4 606 Electromagnetic waves https://www.khanacademy.org/science/10th-grade-melcs/x1cfbe2e54160ac98:2nd-quarter/x1cfbe2e54160ac98:electromagnetic-spectrum/v/x-rays 2020-06-23T07:22:41Z X-rays (1895) NASA video https://cdn.kastatic.org/googleusercontent/xOCnLhhnlvvIG3i670bCEgmuJtaRnPnEFRW2LpAE99GkV4T7bgum6WqsG2B0nJHKq1YVMAFev7799ypJ2_2RlGU X-rays (1895) https://cdn.kastatic.org/ka-youtube-converted/CCAYcuCWOnM.mp4/CCAYcuCWOnM.mp4 170 Electromagnetic waves https://www.khanacademy.org/science/ms-physics/x1baed5db7c1bb50b:waves/x1baed5db7c1bb50b:electromagnetic-waves/v/electromagnetic-waves-and-matter 2025-07-01T10:10:08.145512912Z Electromagnetic waves and matter Electromagnetic (light) waves travel along straight line paths. We can model these paths using rays. When a light ray encounters a boundary between different materials, the light can be reflected, absorbed, and/or transmitted. Most everyday objects don't emit their own visible light. We see these objects when visible light from a source reflects off of the object and into our eyes. Objects that absorb all colors of visible light appear black. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/732a6dc9-a8b8-46dd-81e7-022521e69b88_1280_720_base.png Electromagnetic waves and matter Electromagnetic (light) waves travel along straight line paths. We can model these paths using rays. When a light ray encounters a boundary between different materials, the light can be reflected, absorbed, and/or transmitted. Most everyday objects don't emit their own visible light. We see these objects when visible light from a source reflects off of the object and into our eyes. Objects that absorb all colors of visible light appear black. https://cdn.kastatic.org/ka-youtube-converted/nXuPL8KD2SU.mp4/nXuPL8KD2SU.mp4 456 Electromagnetic waves https://www.khanacademy.org/science/organic-chemistry/spectroscopy-jay/uv-vis-spectroscopy/v/absorption-in-the-visible-region 2023-09-10T17:11:17.624018169Z Absorption in the visible region Explore the physical basis of our perception of color through the example of beta carotene, the molecule that gives carrots their orange color. Beta carotene absorbs light in the visible region of the electromagnetic spectrum at wavelengths of approximately 450 to 500 nanometers, which corresponds to blue light. As a result, the orange wavelengths are reflected, making beta carotene appear orange to our eyes. Jay video https://cdn.kastatic.org/googleusercontent/-BVqSwaO5Of4Om478NOZvpaxjidbpl8aPEJftZ4hZwyzP0Rmv_1nlC30V1l0zqpWmvM9FnLJ-qRmg3JdkbJBfsP8 Absorption in the visible region Explore the physical basis of our perception of color through the example of beta carotene, the molecule that gives carrots their orange color. Beta carotene absorbs light in the visible region of the electromagnetic spectrum at wavelengths of approximately 450 to 500 nanometers, which corresponds to blue light. As a result, the orange wavelengths are reflected, making beta carotene appear orange to our eyes. https://cdn.kastatic.org/ka-youtube-converted/5HMMfiyszjo.mp4/5HMMfiyszjo.mp4 311 Electromagnetic waves