Glossary

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Click on the letter of the topic you are interested in, or use the "find on page option" from your browser to locate specfic terms.


A

Amplitude- A measurement from midpoint to crest (or trough) of a wave.

 

 


B

 


C

Crest- the upper most point on a wave.

 


D

Diffraction – Any bending of light by means other than reflection and refraction.

Doppler Effect – The change in frequency of a wave due to the motion of the source (or due to the motion of the receiver).

 

 


E

Electromagnetic Spectrum – The continuous range of electromagnetic waves that extends in frequency from radio waves to gamma waves.

Electromagnetic Waves – An energy-carrying wave produced when an electric charge accelerates.

 

 


F

Forced Vibrations – The setting up of vibrations in an object by a vibrating source.

Frequency – For a vibrating body, the number of vibrations per unit time. For a wave, the number of crests that pass a particular point per unit time.

 

 


G

 


H

Hertz (Hz)- A unit of frequency. 1 Hertz is equal to 1 wave per 1 second.

 

 

I

Interference – The combined effect of two or more waves overlapping.

 


J

 


K

 


L

Law of Reflection – The angle of reflection equals the angle of incidence.

Longitudinal Wave – A wave in which the medium vibrates in a directional parallel (longitudinal) with the directional in which the wave travels.

 

 


M

 


N

Natural Frequency – A frequency at which an elastic object naturally tends to vibrate.

 

 


O

Opaque – The term applied to materials that absorb light without reemission.

 

 


P

Period – The time required for a vibration or a wave to make a complete cycle. The inverse of frequency.

 


Q

 


R

Reflection - The returning of a wave to the medium from which it came when it hits a barrier.

Refraction - The bending of waves due to a change in the medium.

Resonance – A dramatic increase in the amplitude of a wave that results when the frequency of forced vibrations matches an object’s natural frequency.

 

 


S

 


T

Transparent - The term applied to materials through which light can pass in straight lines.

Transverse Wave – A wave in which the medium vibrates in a direction perpendicular (transverse) to the direction in which the wave travels.

Trough- The lowest point of a wave.

 


U

 


V

 


W

Wave - A disturbance that travels from one place to another transporting energy, but not necessarily matter, along with it.

Wavelength – The distance from the top of one crest to the top of the next one, or, equivalently, the distance between successive identical parts of the wave.

Wave Speed- The velocity of the wave. It can be calculated with the following equation

 


X

 


Y

 


Z