On this page we will examine the wave phenomena of reflection, refraction, interference, diffraction and polarisation, as well as the concept of standing (or stationary) waves.
To show these in a visual way we will use a ripple tank simulation. Wave simulations use the same mathematical equations that are used to model real waves. Therefore they have have the same properties.
Key Concepts
Use quizzes to practise application of theory.
START QUIZ!
The diagram shows a ray of light reflecting off a mirror
The angle of incidence is
angles are measure to the normal
The diagram shows a wavefront incident on then reflecting off a boundary.
Which angle is the angle of reflection?
The angle of reflection is the angle between the ray and the normal. This is the same as the angle shown
This diagram represents a circular wavefront incident on a plane boundary.
Which of the red lines represents the reflected wavefront?
The centre of the reflected wave should be the same distance behind the reflector as the centre of the incident wave is in front.
The diagram represents a plane wavefront passing from medium 1 to 2 with 4 possible angles of refraction.
If the wave speed in 2 is greater than 1 the refracted wave could be:
The wave direction moves towards the normal
The diagram represents a plane wavefront passing from medium 1 to 2 with 4 possible angles of refraction.
If the wave speed in 1 is greater than 2 the refracted wave could be:
The wave direction moves towards the normal
The diagram shows a wave refracting as it passes from one medium to another.
velocity in medium 1/velocity in medium 2 (2dp)
v1/v2 = sin i1/sin i2 = sin 30°/sin70°
A plane wave passes across the boundary from one medium to another as shown.
The ratio velocity in medium 1/velocity in medium 2 is
Since frequency is the same in both media v is proportional to λ (v = fλ)
v1/v2 = λ1/λ2 = 2/1
This is a screenshot from Paul Falstad´s ripple tank simuator
In the blue area the water is
The wave travels slower in the blue area so the water is less deep.
This image is a screenshot from Paul Falstad´s ripple tank simulator
If the difference between distance XP and YP is 2 cm the wavelength is:
P is in the first minimum so path difference = λ/2
This image is a screenshot from Paul Falstad´s ripple tank simulator
If the difference between distance XP and YP is 2 cm the wavelength is:
P is in the first maximum so path difference = λ
This screenshot from Paul Falstad´s ripple tank shows waves diffracting through a single slit
The waves would definitely spread out more if:
reducing the slit width and increasing wavelength both result in a wider angle
This screenshot from Paul Falstad´s ripple tank shows waves diffracting through a single slit
If the slit width is reduced:
angle of diffraction increases and less wave passes through the slit so the amplitude is reduced
The diagram below shows a wave in a string incident on a narrow slit.
When the wave passes though the slit it will:
Only the component in the direction of the slit will pass through.
An unpolarised wave passes along a string. When it meets a vertical slit
I´m not sure what would actually happen but according to this simple model all components in line with the slit will pass.
When a guitar string is plucked, the wave
The wave isn´t normally polarised but can be if you restrict it lightly with your finger.
A standing wave is formed when the wave shown reflects off the fixed end.
The distance between nodes will be:
A standing wave can be formed in a string by vibrating each end. This causes waves to travel along the string in both directions, these waves add to give a standing wave.
To form a standing wave the sources do not have to be
changing the phase wil change the positions of the nodes but a standing wave can still be formed. In practice reflections will confuse the matter
How much of Wave phenomena have you understood?
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