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9Sci CH19
9th Science CH19 Light
Term | Definition |
---|---|
diffraction | the bending of waves around a barrier |
diffraction grating | a piece of glass or plastic with many parallel slits that acts like a prism, causing white light that passes through it to separate into its component colors (the visible spectrum) |
electromagnetic radiation | transverse waves that transfer energy by radiation; vary in length from very long radio waves to extremely short gamma waves |
fluorescent light | light produced when ultraviolet radiation inside a fluorescent light bulb causes its fluorescent coating to glow; uses less energy than incandescent bulbs |
gamma ray | high-frequency electromagnetic waves that travel at the speed of light, have no mass or charge, and are the most penetrating form of radiation |
incandescent light | light produced by a thin tungsten wire, or filament, that is heated until it glows |
infrared radiation | electromagnetic waves that have a wavelength slightly longer than visible light; indicates the presence of heat |
microwave | radio waves with the highest frequency and energy; used in communications and microwave ovens |
modulation | process of adding voice, music, video, computer information, or other data to radio waves by using electrical currents to vary either amplitude or frequency |
opaque material | materials you can’t see through because they absorb or reflect all light |
photon | a tiny particle-like bundle of radiation |
pigment | colored material that absorbs some colors and reflects others; the colors of pigments are determined by the colors they reflect |
radio wave | electromagnetic waves that have long wavelengths (low frequencies); radio waves are used in communications |
reflection | occurs when a wave strikes an object and bounces off |
refraction | the bending of waves, caused by changing their speed |
translucent material | materials that can be hazily seen through because they allow some light to pass through them |
transparent material | materials that can be clearly seen through because they allow light to pass through them |
ultraviolet radiation | electromagnetic waves that have a higher frequency than visible light; abbreviated UV |
visible radiation | electromagnetic waves in the only part of the electromagnetic spectrum that we can see--light |
X-ray | electromagnetic waves having a wavelength shorter (higher frequency) than ultraviolet radiation; often used in medical diagnosis and photography because they can penetrate human tissue |