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Chapter 17 & 18
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 angels ti 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 one cycle, a complete motion that returns to its starting point |
frequency | the number of complete cycles in a given time |
hertz | The measure frequency is measured in, cycles per seconds |
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 | 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 | When two or more waves overlap and combine together |
constructive interference | When two or more waves combine to produce a wave with a larger displacement |
destructive interference | 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 |
node | a point on a standing wave that had 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 exert electric forces on charged particles |
magnetic fields | A region of space produces magnetic forces. |
electromagnetic radiation | The transfer of energy by electromagnetic waves travelling through matter or across 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 the wave is varied |
frequency modulation | The frequency of the wave is varied |
Thermograms | Color-coded pictures that show variations in temperature |