# Science Exam Study Guide: Properties Of Waves And Physics

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Science Exam Study Guide
I. Properties of waves and sound.
a. Know and be able to describe the following:
Wave: A disturbance that transfers energy from place to place
Transverse wave: A wave that moves the medium in a direction perpendicular to the direction in which the wave travels. λ (wavelength): The distance between two corresponding parts of a wave.
Compressional/longitudinal wave: A wave that moves a medium in a direction parallel to the direction in which the wave travels.
Intensity: The amount of energy per second carried through a unit area by a wave
Loudness: Perception of the energy of a sound
Amplitude: The max distance the particles of a medium move from their rest positions as a wave passes through the medium. (Distance from crest or trough to rest position)
Medium: The material through which a wave travels.
Crest: The highest part of a transverse wave.
Trough: The lowest part of a transverse wave.
Rarefaction: The part of a longitudinal wave where the particles of the medium are far apart.
Compression: The part of a longitudinal wave where particles of the medium are close together.
Infrasonic: Sound waves with frequencies below 20 Hz (human audibility).
Ultrasonic: Sound waves with frequencies above 20,000 Hz (human audibility).
Frequency: The # of complete waves that pass a given point in a certain amount of time
Pitch: Perception of the frequency of a sound.
Doppler Effect: The change in frequency of a wave as its source moves in relation to an observer. Pitch of a moving sound is higher when closer; crests are closer together.
Velocity: The speed of something in a given direction.
Speed of sound: At 20 degrees Celsius, about 343 m/s. Direct variation between elasticity and sound/ temp. and sound. Inverse variation between density and sound.
Wave interference: The interaction between waves that meet.
Constructive: When waves combine to make a wave with a larger amplitude
Destructive: When waves combine to make a wave with a smaller amplitude
Resonance: The increase in the amplitude of a vibration that occurs when external vibrations match an object’s natural frequency.
Closed-end air column: Consists of a tube with one end closed off. Refer to packet.
b. Transverse Wave: Draw a transverse wave diagram when given amplitude, wavelength.
II. The Electromagnetic Spectrum http://www.darvill.clara.net/emag/index.htm
a. List the 7 types of electromagnetic radiation in order from longest to shortest wavelength. Relationship between frequency and wavelength of an EM wave?
Radio wave, Microwave, Infrared, Visible light, Ultraviolet, Soft X-Rays, Hard X-Rays, Gamma Rays
The higher the frequency, the lower the wavelength
Wavelengths above visible light: waves. Shorter: Rays
b. The colors of visible/optical light: Know the 7 colors in order from lowest energy.
Lowest energy: RED. Then ORANGE, YELLOW, GREEN, BLUE, INDIGO, VIOLET!
Note: Red has the longest wavelength
c. How is photon energy related to wavelength/frequency of electromagnetic waves?
Wavelength: Inverse variation between photon energy and wavelength
Frequency: Direct variation (as energy increases, so does frequency)
d. Applications and dangers of electromagnetic radiation: What are the major uses and dangers of the seven types of electromagnetic radiation?