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Ch. 17 Vocab
Vocabulary terms for chapter 17
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 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 a complete motion that returns to the starting point |
Frequency | The number of complete cycles in a given time |
Hertz | Frequency is measured in cycles per second, or Hertz |
Wavelength | The distance between a point on one wave and the same point on the next cycle of the wave |
Amplitude | The maximum displacement of the medium from its rest position |
Reflection | What occurs when a wave bounces off a surface that it cannot pass through |
Refraction | 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 smaller displacements |
Standing Wave | A wave that appears to stay in one place and 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 magnetic fields |
electric field | a region of space exerts electric forces on charged particles |
magnetic field | a region of space that produces magnetic forces |
electromagnetic radiation | the transfer of energy by electromagnetic waves passing through matter or space |
photoelectric effect | The emission of electrons from a metal caused by light striking the metal |
photons | 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 a wave is varied |
frequency modulation | the frequency of a wave is varied |
thermograms | color-coded pictures that show variations in temperature |