wave
a disturbance in matter that carries energy from one place to another
medium
material through which a mechanical wave travels such as air, water, soil, glass
Which type of wave can travel through a vacuum?
electromagnetic waves
Which type of waves require matter (a medium) to travel though?
mechanical waves
Crest
The highest point of the wave above the rest position
Trough
The lowest point of the wave below the rest position
Transverse wave
A wave in which particles of medium move PERPENDICULAR to the direction in which the wave travels
Compression
An area of a longitudinal wave where the particles in a medium are spaced close together
Rarefaction
An area of a longitudinal wave where the particles in a medium are spread out
Longitudinal wave
A wave in which the movement of the medium particles is PARALLEL to or in the same direction as the direction the wave travels
What is frequency measured in?
wave cycles per second or hertz (Hz)
Wavelength
The distance between a point on one wave and the same point on the next cycle of the wave such as from crest to crest
How is wavelength measured for a transverse wave?
It is the distance measured between two crests or between two troughs
How is wavelength measured for a longitudinal wave?
It is the distance between one compression to the next compression
What does increasing the frequency of a wave do to its wavelength?
The wavelength decreases
How do you calculate speed of a wave?
Speed= Wavelength x Frequency
Amplitude
The maximum displacement of the medium from its rest position; 1/2 the wave height
An increased amplitude of a sound wave results in
greater loudness and energy
Sound waves
compressions and rarefactions that travel through a medium; they are longitudinal waves
high frequency sound
high pitch sound that adults are gradually unable to hear with age
High frequency sounds have a __________ pitch, and low frequency sounds have a ______ pitch
high; low
If the speed of a wave is 335 m/s and its frequency is 67 Hz, what is its wavelength?
5 m; speed divided by frequency= wavelength
Which type of medium does sound travel fastest though?
usually the most dense, rigid solids
Does sound travel faster through solids, liquids, or gases?
Sound travels fastest in solids because the particles in a solid are closer together than in liquids or gas
electromagnetic waves
A form of energy that can move through the vacuum of space.
longest wavelength form of electromagnetic radiation
radio waves
order of visible light colors from lowest energy to highest energy
Red, Orange, Yellow, Green, Blue, Indigo, Violet
Which type of electromagnetic radiation is used to kill cancer cells?
gamma rays
Reflection
The bouncing back of a wave when it hits a surface through which it cannot pass.
Refraction of light
The bending of light as it passes from one medium to another
Type of electromagnetic radiation needed by the skin to make vitamin D. It can be used to kill bacteria.
Ultraviolet radiation
Type of electromagnetic radiation with lowest frequency and longest wavelength; used in Wi-Fi, radio, radar, and television.
radio waves
Which is higher in energy, infrared waves or ultraviolet waves?
ultraviolet
Find the wavelength of a wave in meters whose speed is 60 m/s and whose frequency is 2 Hz.
30 m
Find the frequency of a wave whose wavelength is 4 m and speed is 20 m/s.
5 Hz
Calculate the wavelength of electromagnetic radiation if the frequency is 6.10 x 10¹⁴Hz? The speed of light is 3.0 x 10⁸ m/s.
4.9 x 10⁻⁷ m
What are x-rays?
type of electromagnetic waves used for medical imaging; higher in energy and shorter wavelength than ultraviolet
Type of electromagnetic radiation used by remote controls
infrared
Type of electromagnetic radiation used by GPS satellites and doppler radar
microwaves
How does the speed of visible light compare to ultraviolet light?
they have the same speed
How does the speed of visible light compare with the speed of gamma rays, when both speeds are measured in a vacuum?
they have the same speed
What happens to the speed of light when light passes through a medium such as glass?
the speed is slower
What does AM stand for?
amplitude modulation
What does FM stand for?
Frequency Modulation
How does analog signal compare to digital signal?
Analog signal is a continuous signal which represents physical measurements. Digital signals are discrete time signals generated by digital modulation.
What is the energy of a long wavelength wave?
low energy
What is the energy of a high frequency wave?
high energy
Does red light or yellow light have a longer wavelength?
red light
What is the wavelength of a wave?
the distance between two of the same points on a wave
What is resonance?
the response of a standing wave to another wave of the same frequency
Hearing damage may occur in humans if they are excessively exposed to noise above:
90 dB
Sounds at this level cause pain and damage to your hearing
120 dB
The process of adding an information signal to a carrier radio wave is called__.
modulation
A system of orbiting satellites, ground monitoring stations, and receivers that determine an exact location on Earth by sending microwave signals.
Global Positioning System
The unit of frequency is _____.
Hertz (Hz)
Unit of speed
meters per second (m/s)
unit of wavelength
meters (m)
Sound is an example of what kind of wave?
longitudinal wave
What is a vacuum?
an empty space with no particles and no pressure; no medium
The law of reflection states
the angle of incidence is equal to the angle of reflection
An echo occurs when sound
is reflected from a surface
How close together the particles of the medium are in the compressions of a longitudinal wave determines which property of the wave?
amplitude
Which type of electromagnetic waves cause you to feel warmer when you stand near a fire?
infrared
Which type of electromagnetic waves have the highest energy?
gamma rays
Which is the term for an electromagnetic wave with the specific frequency that a radio station is assigned?
carrier wave
Which best describes the function of a transceiver?
transmits and receives signals
How can you prevent damage to the hair cells of the cochlea of your ears?
Avoid loud music and wear earplugs when exposed to sounds that are 90 dB or greater such as gunshots and workplace noise
Calculate the wave speed for a wave with a wavelength of 2 m and a frequency of 0.3 Hz.
0.6 m/s
unit of sound intensity
decibel (dB)
Does light travel faster in air or water?
air
Does sound travel faster in air or water?
water