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Ch 17&18 vocab
| Term | Definition |
|---|---|
| Mechanical Wave | A disturbance in matter that carries energy from one place to another. |
| Medium | The material through which a wave travels. |
| Crest | The highest point of a transverse wave. |
| Trough | The lowest point of a transverse wave. |
| Transverse Wave | A wave that causes a medium to vibrate at right angles to the direction in which the wave travels. |
| Compression | An area of a longitudinal wave where the particles of the medium are close together. |
| Rarefaction | An area of a longitudinal wave where the particles of the medium are spread out. |
| Longitudinal Wave | A wave in which the vibration of the medium is parallel to the direction the wave travels. |
| Surface Wave | A wave that travels along a surface separating two media. |
| Periodic Motion | Any motion that repeats at regular time intervals. |
| Period | The time required for one complete cycle of a periodic motion. |
| Frequency | The number of complete cycles per unit time for a periodic motion. |
| Hertz | A unit of measurement for frequency, equal to one cycle per unit. |
| Wavelength | The distance between a point of a wave and the same point on the next cycle on the wave. |
| Amplitude | The maximum displacement of a medium from the rest position. |
| Reflection | The interaction that occurs when a wave bounces off a surface that it cannot pass through. |
| Refration | The bending of a wave as it enters a new medium at an angle. |
| Diffraction | The bending of a wave as it moves around an obstacle or passes through a narrow opening. |
| Interference | The interaction of two or more waves that combine in a region of overlap. |
| Constructive Interfernce | The interaction among two or more waves in which displacements combine to produce a wave with a larger displacement. |
| Destructive Interference | The interaction among two or more waves in which displacement combine to produce a wave with a smaller displacement. |
| Standing Wave | A wave that appears to stay in on place and does not seem to move through a medium. |
| Node | A point on a standing wave that has no displacement from the rest position. |
| Antinode | A point of maximum displacement midway between two nodes in a standing wave. |
| Electromagnetic Waves | A transverse wave consisting changing and changing magnetic fields. |
| Electric Field | A field in a region of space that exerts electric forces on charged particles. |
| Magnetic Field | A field in a region of space that exerts magnetic forces. |
| Electromagnetic Radiation | The transfer of energy by electromagnetic waves. |
| Photoelectric Effect | The emission of electrons from a metal caused by light striking the metal. |
| Photons | A packet of electromagnetic energy. |
| Intensity | The rate at which a wave's energy flows through a given unit of area. |
| Electromagnetic Spectrum | The full range of electromagnetic radiation. |
| Amplitude Modulation | A method of transmitting a radio signal in which the amplitude of the carrier wave varies while its frequency remains the same. |
| Frequency Modulation | A method of transmitting a radio signal in which the frequency of the carrier wave varies while the amplitude remains the same. |
| Thermograms | A color-coded picture using variations in infrared radiation to show variations in temperature. |