Module 3: Waves and the Electromagnetic Spectrum Flashcards
(52 cards)
Define Amplitude
the maximum displacement on either side of the euqilibriium (midpoint) position
Define Frequency
the number of vibrations per unit time; for a wave the number of crests that pass a particular point per unit time
Define Period
time required for a vibration or a wave to make a complete cycle; equal to 1/frequency
Define Wavelength
the distance between successive crests, throughs, or identical parts of a wave
Define Longitudinal Waves
a wave in which the medium bibrates ina direction parallel (longitudinal) to the direction in which the wave travels; light consists of transverse waves
Define Transverse Waves
a wave in which the medium vibrates in a direction perpendicular (transverse) to the direction in which the wave travels; light consists of tranverse waves
Define Reflection
the returning of a wave to the medium from which it came when it hits a barrier
Define Refraction
the path of a wave bends due to moving from one medium to another
Define Diffraction
spreading of wave when passing through a hole
Define Interference
the interaction of two or more waves with each other
Defne Doppler Effect
the change in frequency of a wave due to the motion of the source (or due to the motion of the receiver)
Define Sound
created when air molecules are vibrated back and forth by a vibration
Define Pitch
the quality of sound governed by the rate of vibrations producing it; the degree of highness or lowness of a tune
- low frequency = low pitch
- high frequency = high pitch
Define Volume
corresponds to the amplitude of the sound wave
- larger amplitude = louder sound
- smaller amplitude = softer sound
Describe what a wave is
an oscillation accompanied by a trasfer of energy that travels through a medium (space or mass); wave motion transfers energy from one point to another, which displaces particles of the transmission medium
Explain the difference between a Transverse Wave and a Longitudinal Wave. Give examples of each.
- Transverse Wave
- motion occurs perpendicular to the direction of travel of the wave; think of a boat riding ocean waves
- examples: light waves, an oscillation string, seismic s-waves
- Longitudinal Wave
- motion occurs parallel to the direction of travel of the wave; think of a slinky laying on the ground and you push one end towards the other
- examples: sound waves, pressure waves, seismic p-waves (generated by explosions and earthquakes)
- FYI - Think of a long line of people holding hands. When one person jumps in the air still holding hands, this causes a chain reaction in making the next person jump up an so on and so on. This is a transverse wave. Now that same line, if the person bumps the person next to them, this will cause a chain reaction with people with bumping and bouncing off of one another. This is longitudinal wave.
Describe the below term associated with waves:
- Wavelength
the distance between successive crests, troughs or identical parts of a wave
Describe the below term associated with waves:
- Frequency
the number of vibrations per unit time; for a wave, the number of crests that pass a particular point per unit time
Describe the below term associated with waves:
- Amplitude
the maximum displacement on either side of the equilibrium (midpoint) position
Define Reflection and give an example.
Definition: occurs when a wave encounters a barrier; involves bouncing waves off an opaque surface
Examples: light bouncing off a mirror, voices bouncing off of a rock wall (also called echoes)
Define Refraction and give an example.
Definition: a wave moving from one medium to another, the wave bends at this point
Example:looking at a straw in a clear glass of water, earthquakes
Define Interference. Explain how constructive and destructive interfernce differ.
Definiton: occurs when waves interact with each other
- Constructive
- amplidtude gets bigger
- increase in sound
- light would get brighter
- Destructive
- will cancel each other out
- instead of light you would get dark
- reduces noise
- example is noise cancelling headphones
Define the Doppler Effect and describe what happens to a wave due to it.
Definition: the change in frequency of a wave due to the motion of the source (or due to the motion of the receiver)
Example: the sound a car makes when it drives past you really fast
- Sound Wavelength (Longitudinal Wave)
* the wave length will have a higher frequency as it travels twoard the objet (or a higher pitch), when it travels past the object the wavelength will lengthen and you will have a lower frequency (or a lower pitch) - Light Wavelength (Transverse Wave)
* the Doppler Radar station uses radar (a form of light) to track storms; they bounce the radio waves off the storm clouds if they send the radio waves towards the on-coming* storm, the wavelengths will be shorter, higher frequencies; if they send the radio waves towards *outgoing storm, the wavelengths will get longer, lower frequencies
A train travels toward you, emitting a horn at a frequency of 256 Hz. Due to the Doppler Effect, the frequency of sound that you hear is acutally:
- higher than 256 Hz
- lower than 256 Hz
- equal to 256 Hz
- higher than 256 Hz
