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Kala Stevenson
Chapter 17 vocabulary
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 the wave above the rest position. |
trough | The lowest point below the rest position. |
transverse wave | A wave that causes the medium to vibrate at right angles to the direction in which the wave travels. |
compression | An area where the particles in a medium are spaced close together. |
rarefaction | An area where the particles in a medium are spaced 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 cycle, a complete motion that returns to its starting point. |
frequency | The number of complete cycles in a given time. |
hertz | How frequency is measured, cycles per second. |
wavelength | The distance between a point on one wave and the same point on the next cycle of the wave. |
amplitude | Is the maximum displacement of the medium from its rest position. |
reflection | Occurs when a wave bounces off a surface that it cannot pass through. |
refaction | 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 | Occurs when two or more waves overlap and combine together. |
constructive interference | Occurs when two or more waves combine to produce a wave with a larger displacement. |
destructive interference | Occurs when two or more waves combine to produce a wave with a smaller displacements. |
standing wave | A wave that appears to stay in one place-- it does not seem to move through the medium. |
node | A point on a standing wave that has no displacement from the rest position. |
antinode | A point where a crest or trough occurs midway between two nodes. |
electromagnetic waves | transverse waves consisting of changing electric fields and changing magnetic fields. |
electric field | A region of space exerts electric forces on charged particles. |
magnetic field | A region of space produces magnetic forces. |
electromagnetic radiation | The transfer of energy by electromagnetic waves traveling through matter or across space. |
photoelectric effect | The emission of electrons from a metal caused by light striking the metal. |
photons | These packets 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 frequencies of electromagnetic radiation. |
amplitude modulation | The amplitude of the wave is varied. The frequency stays the same. |
frequency modulation | The frequency of the wave is varied.The amplitude remains the same. |
thermograms | Are color-coded pictures that show variations in temperature. |