3. Waves Flashcards
What do waves do
Waves transfer energy and information without transferring matter
Define frequency and give its units
● The number of waves passing through a point per second.
● Hz (hertz)
Define wavelength
The distance between two adjacent
peaks on a wave
Define amplitude
● The maximum displacement of the
wave from its equilibrium position.
● The distance between the centre of
the wave and a peak
What is meant by the period of the
wave?
The length of time it takes for ONE FULL WAVE to pass through a point
How can you calculate the wave speed?
● Wave speed (measured in metres per second) is equal to the product of the wavelength and the frequency of the wave.
● Wave velocity= f ×λ
State an equation linking frequency and
period of a wave
frequency (Hz) = 1/ time period
f = 1/T
What is a longitudinal wave? Give some
examples
● Vibrations are parallel to the direction of
energy transfer(wave)
● Examples include sound waves and
earthquakes (seismic waves)
What is a transverse wave? Give some
examples.
● A wave with oscillations that are perpendicular ( 90 degrees) to the direction of energy transfer. ● Examples include electromagnetic waves
Explain what is meant by “the Doppler effect”
Apparent change in the frequency of a wave caused by relative motion between the source of the wave and the observer. When a wave source is moving towards the observer, observed frequency increases and observed wavelength decreases; when a wave source is moving away from the observer, observed frequency decreases and observed wavelength increases since v= f ×λ and speed in constant
At what speed does an electromagnetic
wave travel in a vacuum?
3 x10^8 m/s
What types of waves are electromagnetic waves?
Transverse
What do electromagnetic waves
transfer?
Energy and Information
What are the four common properties of all electromagnetic waves?
· They are all transverse waves
· They all transfer energy or information
· They all travel at the speed of light in vacuum
· They all can be reflected, refracted or diffracted
Which part of the electromagnetic spectrum has the longest wavelength?
Radio waves
Order the electromagnetic spectrum from
the highest frequency to the lowest
frequency
Gamma rays, x-rays, ultraviolet, visible
light, infrared, microwaves and radio
waves
What are the colours of the visible light spectrum?
Red, Orange, Yellow, Green, Blue, Violet
a. Which colour has the highest frequency?
b. Which colour has the lowest frequency?
c. Which colour has the lowest wavelength?
d. Which colour has the highest wavelength?
a. Violet
b. red
c. violet
d. red
What are the uses of radio waves?
● For communication through radio
● Used for satellite transmissions
What are microwaves used for?
● Cooking in microwaves ovens
● Communications
● Satellites