Waves Flashcards
Which wave in the electromagnetic spectrum has the shortest wavelength?
Gamma rays have the shortest wavelength.
The diagram shows what would happen if waves of a short wavelength approach an obstacle.
What would be observed if the waves had a long wavelength?
Long wavelengths diffract more than short wavelengths.
Therefore the waves would bend around the obstacle more.
What does the prefix m stand for?
m stands for milli
milli = x 10-3
Describe what is meant by gamma radiation.
- Gamma radiation is a wave in the electromagnetic spectrum
- Gamma rays have no mass or charge
- Gamma rays have a very short wavelength and a high frequency
What happens to the speed of a ray of light as it goes from glass into air?
As a ray of light goes from glass into air, its speed increases.
(the light speeds up in a medium which is less optically dense)
What does the prefix G stand for?
G stands for giga
giga = x 109
What is the unit for period?
(period of a wave)
The unit for period is seconds (s)
What does the prefix n stand for?
n stands for nano
nano = x 10-9
What type of wave is a water wave an example of?
A water wave is an example of a transverse wave.
What is being shown in this diagram?
This is diffraction - the bending of waves around an obstacle.
What is the unit for wavelength?
The unit for wavelength is metres (m)
Give one application of radio waves.
- Broadcasting
- Satellite transmissions
- Communications
Give one use of visible light.
- photography
- illumination
- car headlights
- street lighting
Give one use of gamma rays.
- sterilising food and medical equipment
- treating cancer
- medical tracers
State one source of visible light.
Sources of visible light include:
- the Sun
- light bulbs
- anything hot enough to glow
What type of wave is a sound wave an example of?
A sound wave is an example of a longitudinal wave.
What is meant by the wavelength of a wave?
Wavelength is the distance between a point on one wave and the same point on the next wave.
Give one use of X-rays.
- medical X-ray scans
- airport security scanners
Does a ray of light always change direction when it undergoes refraction?
No - not always. A ray of light which enters a material at 90° to the surface will not change direction.
(e.g. middle ray in diagram)
Name the three quantities shown in this formula.
v = speed
f = frequency
λ = wavelength
(λ is called ‘lambda’)
Which wave in the electromagnetic spectrum has the longest wavelength?
Radio waves have the longest wavelength.
What is the unit for speed?
The unit for speed is metres per second (ms-1)
What happens to the speed of a ray of light as it goes from air into glass?
As a ray of light goes from air into glass, its speed decreases.
(the light slows down in a medium which is more optically dense)
What is meant by refraction?
(in terms of waves)
Refraction is the change of speed (of a wave) caused by entering a different medium (e.g. air to glass).
Name the three quantities shown in this formula.
d = distance
v = speed
t = time
What is meant by the frequency of a wave?
Frequency is the number of waves per second.
Name an example of a longitudinal wave.
Sound waves are longitudinal waves.
A ray of light exits a block of glass (as shown). Describe the path of the ray of light after it exits the glass.
The ray of light bends away from the normal as it exits the glass.
What type of wave are microwaves an example of?
Microwaves are an example of transverse waves.
In the diagram shown, what is the dotted line and what is important about where it is?
The dotted line is the normal.
The normal is at 90° to the surface of the medium.
What does the prefix M stand for?
M stands for mega
mega = x 106
Name the two quantities shown in this formula.
T = period
f = frequency
What is the unit for distance?
The unit for distance is metres (m)
State a detector of radio waves.
An aerial is used to detect radio waves.
What does the prefix k stand for?
k stands for kilo
kilo = x 103
Give one use of ultraviolet.
- security marking
- detecting forged bank notes
- fluorescent lamps
What does the prefix µ stand for?
µ stands for micro
micro = x 10-6
What is the unit for time?
The unit for time is seconds (s)
Which wave in the electromagnetic spectrum has the least energy?
Radio waves have the least energy.
From the diagram shown, identify the wavelength of the wave.
C is the wavelength.
From the diagram shown, identify the amplitude of the wave.
D is the amplitude.
What do all waves in the electromagnetic spectrum have in common?
All waves in the electromagnetic spectrum travel at the same speed (the speed of light).
What is meant by the amplitude of a wave?
The amplitude of a wave is the height of the wave.
How is the frequency of a wave in the e.m. spectrum related to its energy?
The higher the frequency of a wave in the e.m. spectrum, the more energy the wave has.
What speed do all waves in the electromagnetic spectrum travel at?
All waves in the electromagnetic spectrum travel at the speed of light - 3 x 108 ms-1.
Which wave in the electromagnetic spectrum has the greatest energy?
Gamma rays have the greatest energy.
State a detector of infrared radiation.
- photodiode
- phototransistor
- thermistor
- thermocouple
In the diagram shown, what do the symbols i and r represent?
i = angle of incidence
r = angle of refraction
A ray of light enters a block of glass (as shown). Describe the path of the ray of light after it enters the glass.
The ray of light will bend towards the normal as it enters the glass.
Give one use of infrared.
- thermal imaging
- remote controls
- security systems
Name the seven different types of waves in the electromagnetic spectrum.
Try to list them from long λ (wavelength) to short λ.
Radio (long λ)
Microwaves
Infrared
Visible
Ultraviolet
X-rays
Gamma rays (short λ)
What is the unit for frequency?
The unit for frequency is hertz (Hz)
What is meant by diffraction?
Diffraction is the bending of waves around an obstacle.
Give one application of microwaves.
- cooking
- mobile phone communications
What is meant by the period of a wave?
The period of a wave is the time taken for one wave to pass.
Complete the following sentence:
All waves carry ……………
All waves carry energy.
What is meant by the statement “A source of waves has a frequency of 16 Hz” ?
This means that there are
16 waves per second
generated by the source.
