Waves (Basic) Flashcards
What is a wave?
A wave is an oscillation in a medium.
Waves can transfer energy and information.
What is an ‘oscillation’?
An oscillation is another word for a vibration.
When discussing waves, what is meant by the word ‘medium’?
A ‘medium’ is the material through which a wave passes.
What is the medium for surface waves in the ocean?
Water is the medium.
What is the medium for sound waves in this room?
Air is the medium.
What is the medium for waves on a slinky?
The slinky is the medium.
Give the definition of ‘wave direction’
‘Wave direction’ is the direction in which the wave transfers energy.
Give the definition of ‘a transverse wave’
A transverse wave is a wave where the medium oscillates perpendicular to the direction of energy transfer.
Give the definition of ‘a longitudinal wave’
A longitudinal wave is a wave where the medium oscillates parallel to the direction of energy transfer.
Give three examples of transverse waves
Waves on the surface of the ocean
Light waves
Infra-red waves
(also: all electromagnetic waves are transferse, e.g. radio, microwave, UV)
Give three examples of longitudinal waves
P-waves from an earthquake
Sound waves
Ultrasound waves
What is meant by the ‘wavelength’ of a wave?
The wavelength is the distance between two neighbouring peaks (or two troughs) on a wave.
What are the units of wavelength?
Wavelength is a length, and like all lengths it is measured in metres. (m)
What is meant by the ‘period’ or ‘time period’ of a wave?
The time period of a wave is the time for one complete oscillation to occur.
What are the units of ‘period’?
The ‘period’ or ‘time period’ of a wave is a time, and like all times it is measured in seconds. (s)
What is meant by the frequency of a wave?
The number of complete oscillations that pass a point, per second.
What are the units of frequency?
The units of frequency are Hertz. (Hz)
Define the ‘amplitude’ of a wave.
The amplitude is the maximum displacement caused by a wave.
OR The amplitude is the displacement from the line of zero displacement to the peak of a wave.
What are the units of amplitude?
Amplitude is a distance, so the units of amplitude are metres. (m)
You hear two sound waves. The second wave has the same frequency as the first, but a bigger amplitude. How does it sound different?
It sounds louder.
You have to say ‘louder’ at GCSE. ‘Loud’ would be marked wrong.
You hear two sound waves. The second wave has the same amplitude as the first, but a bigger frequency. How does it sound different?
It sounds higher pitched.
You have to say ‘higher’ at GCSE. ‘High’ would be marked wrong.
You see two light waves. The second wave has the same amplitude as the first, but a bigger frequency. How does it look different?
It is a different colour.
It would be closer to the blue end of the spectrum that the first light wave
You see two light waves. The second wave has the same frequency as the first, but a bigger amplitude. How does it look different?
It looks brighter.
You have to say ‘brighter’ at GCSE. ‘Bright’ would be marked wrong.
What does the symbol ‘λ’ stand for, and what units is it measured in?
The symbol ‘λ’ stands for wavelength. Wavelengths are measured in metres. (m)
What does the symbol ‘f’ stand for, and what units is it measured in?
The symbol ‘f’ stands for frequency. Frequencies are measured in Hertz. (Hz)
In the waves topic, what does the symbol ‘T’ stand for, and what units is it measured in?
In the waves topic, ‘T’ stands for the ‘time period’ of a wave. It is measured in seconds. (s)
In the waves topic, what does the symbol ‘A’ stand for, and what units is it measured in?
In the waves topic, ‘A’ stands for the amplitude of a wave. Amplitudes are measured in metres. (m)
What equation links the number of waves that pass a point, the wave frequency and the time taken?
frequency = number of waves ÷ time taken (for them to pass a point)
120 waves pass a point in 10 seconds. What is the wave frequency?
120 ÷ 10 = 12 Hz
This means 12 waves every second
5 waves pass a point in 10 seconds. What is the wave frequency?
5 ÷ 10 = 0.5 Hz
This means half a wave every second
Name two things that all electromagnetic waves have in common
They all travel at the speed of light in a vacuum
They are all transverse waves
Which electromagnetic wave is used to transmit TV signals?
Radio waves
Which electromagnetic wave is also known as ‘thermal radiation,’ and is emitted by warm objects?
Infrared radiation
Which electromagnetic wave can be used to view security markings?
Ultraviolet
Which electromagnetic wave is used to create shadow pictures of bones?
X-rays
Which electromagnetic wave is used to sterilise medical equipment?
X-rays OR gamma rays
Which electromagnetic wave is used to cook a cheese toastie on a grill?
Infrared radiation
Which waves are used for both radar and for mobile phone transmissions?
Microwaves
Which electromagnetic wave can cause eye damage?
Ultraviolet radiation
Which electromagnetic wave can cause burns to the skin?
Infrared radiation
Which electromagnetic wave can be detected by the human eye?
Visible light
Which electromagnetic wave can cause skin cancer?
Ultraviolet radiation
Which electromagnetic wave can be used to kill cancer cells?
X-rays OR gamma rays
What is the risk of exposure to X-rays and gamma rays?
They can both cause cancer
Which waves have the higher frequency, radio or microwaves?
Microwaves
Which waves have the longer wavelength, ultraviolet or infrared?
Infrared
Which waves have the lower frequency, X-rays or microwaves?
Microwaves
Which waves have the shorter wavelength, gamma rays or visible light?
Gamma rays
Which waves travel faster in a vacuum, visible light or ultraviolet?
Trick question! They travel at the same speed. All electromagnetic waves travel at the speed of light in a vacuum.
Which waves have the shorter wavelength, visible light or microwaves?
Visible light
Which waves have the higher frequency, X-rays or ultraviolet?
X-rays
Which waves have the longer wavelength, microwaves or infrared?
Microwaves
Which waves have the lower frequency, visible light or radio waves?
Radio waves
Which of these are longitudinal waves: radio waves, visible light or ultraviolet radiation?
Trick question! None of them. All electromagnetic waves are transverse.
What is the highest frequency sound a human being can hear?
20,000 Hz
What is the name for sound waves with a frequency above 20,000 Hz?
Ultrasound
What is the lowest frequency sound a human being can hear?
20 Hz
Are ultrasonic waves transverse or longitudinal?
Ultrasonic waves are longitudinal. (All sound waves are longitudinal. Ultrasound is simply sound that is too high pitched for us to hear)
Name two uses of ultrasonic waves
Any two from: • Cleaning jewellery • Checking for cracks in railway tracks • Echolocation (Sonar) • Imaging the foetus in the womb (You must use this phrase! "pictures of babies" = zero marks)
