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Define travelling waves.
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Define travelling waves.
Travelling waves are oscillations that transfer energy from one place to another without transferring matter.
How are waves generated?
Waves are generated by oscillating sources.
Define the displacement of a wave.
The displacement of a wave is the distance of a point on the wave from its equilibrium position.
Define the wavelength of a wave.
The wavelength of a wave is the length of one complete oscillation measured from the same point on two consecutive waves.
Define the amplitude of a wave.
The amplitude of a wave is the maximum displacement of an oscillating wave from its equilibrium position.
Define the period of a wave.
The period of a wave is the time taken for a complete oscillation to pass a fixed point.
Define the frequency of a wave.
The frequency of a wave is the number of complete oscillations to pass a fixed point per unit time.
Define wave speed.
Wave speed is the distance travelled by a wave per unit time.
State the equation linking the frequency of a wave to its period.
The equation linking the frequency of a wave to its period is or
Where:
= frequency, measured in hertz (Hz)
= period, measured in seconds (s)
State the equation for wave speed.
The equation for wave speed is
Where:
= wave speed, measured in metres per second (m s–1)
= frequency, measured in hertz (Hz)
= wavelength, measured in metres (m)
True or False?
The unit hertz is equivalent to per second.
True.
The unit hertz (Hz) is equivalent to per second (s–1).
True or False?
As wavelength increases, frequency decreases for a wave at a constant speed.
True.
As wavelength increases, frequency decreases for a wave at a constant speed.
Define a transverse wave.
A wave is transverse if the oscillations are perpendicular to the direction of wave motion and energy transfer.
Define a longitudinal wave.
A wave is longitudinal if the oscillations are parallel to the direction of wave motion and energy transfer.
True or False?
Longitudinal waves can travel through a vacuum, while transverse waves cannot.
False.
Transverse waves can travel through a vacuum, while longitudinal waves cannot.
Define a rarefaction.
A rarefaction is an area of low pressure in a longitudinal wave, where the particles are further apart from each other.
Define a compression.
A compression is an area of high pressure in a longitudinal wave, where the particles are closer together.
Give an example of a transverse wave.
Examples of transverse waves are:
electromagnetic waves
surface water waves
vibrations on a guitar string
seismic S-waves (secondary waves)
Give an example of a longitudinal wave.
Examples of longitudinal waves are:
sound waves
ultrasound
seismic P-waves (primary waves)
tsunami wave
True or False?
Soundwaves are transverse waves and need a medium in which to propagate.
False.
Soundwaves are longitudinal waves, but they do need a medium in which to propagate.
True or False?
Infrasound waves are waves with frequencies above the range of human hearing.
False.
Infrasound waves are waves with frequencies below the range of human hearing.
State the frequency range of human hearing.
The frequency range of human hearing is 20 Hz to 20 000 Hz.
Define ultrasound.
Ultrasound waves are waves with frequencies above the range of human hearing, >20 kHz.
True or False?
Sound waves with higher frequencies have a higher pitch.
True.
Sound waves with higher frequencies have a higher pitch.
True or False?
Sound waves with larger amplitudes have a lower volume.
False.
Sound waves with larger amplitudes have a greater volume.
True or False?
The temperature of the air affects the speed of sound travelling through it.
True.
The temperature of the air affects the speed of sound travelling through it.
The higher the temperature of the air, the faster sound can travel.
True or False?
Sound travels faster in gases than in solids.
False.
Sound travels faster in solids than in gases.
This is because the particles in a solid are closer together, so they can transfer energy through oscillations more quickly than in a gas.
How is an electromagnetic wave generated?
An electromagnetic wave is generated by the combined oscillation of an electric and a magnetic field.
True or False?
In an electromagnetic wave, the electric and magnetic fields oscillate parallel to each other.
False.
In an electromagnetic wave, the electric and magnetic fields oscillate perpendicularly to each other.
True or False?
Electromagnetic waves can travel through a vacuum.
True.
Electromagnetic waves can travel through a vacuum.
At what speed does a gamma wave travel through the vacuum of space?
A gamma wave travels through the vacuum of space at the speed of light, .
All electromagnetic waves travel at this speed.
Which type of electromagnetic radiation has the lowest energy?
The type of electromagnetic radiation with the lowest energy is radio waves.
This is because the lower the frequency of the EM wave, the less energy it transfers. Radio waves have the lowest frequency and therefore the lowest energy.
Which electromagnetic waves have a shorter wavelength than ultraviolet waves?
The electromagnetic waves with a shorter wavelength than ultraviolet are:
x-rays
gamma rays
Which part of the visible spectrum has wavelengths in the region of 700 nm?
The part of the visible spectrum which has wavelengths in the region of 700 nm is red light.
What is the range of wavelengths that human eyes can detect?
The range of wavelengths that human eyes can detect is called the visible spectrum. The visible spectrum has wavelengths between 400 nm and 700 nm.
What type of wave requires a medium, and can be either transverse or longitudinal?
Mechanical waves require a medium, and can be either transverse or longitudinal.
What type of wave does not require a medium, and travels at the speed of light?
Electromagnetic waves do not require a medium, and travel at the speed of light.