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70 Cards in this Set
- Front
- Back
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What do waves carry? |
Energy, which they transfer from place to place. |
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A Simple Diagram of a Wave includes... |
* Amplitude * Crest * Trough * Wavelength * Node |
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Define Phase |
Two points on a wave are in phase if, at any particular instant, they have the same displacement and velocity |
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What is Amplitude? |
The maximum size of the particle displacement from an undisturbed state. |
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What Symbol is wavelength Represented by? |
λ or Λ (lambda) |
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What is Frequency? |
The number of waves that pass a fixed point per second. The frequency of waves is measured cycles per second or hertz (Hz) In one Hertz there is one cycle or wavelength passing a point per second. |
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What is a Period? and How is it Related to the Frequency? |
The time it takes a single wave to pass a fixed point (T). The period and frequency are related through a reciprocal relationship f= 1/t and T=1/f |
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The Equation for the Velocity of a Wave is ? |
v=fλ That is the frequency by the wavelength. |
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Define Propagate |
To transmit through space or a medium. |
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What is the Source of All Waves? |
Vibration. The energy that vibration passing from the place of origin to a place further away is the wave. |
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Do Waves Transfer Matter? |
No. Waves transfer energy without transferring matter. |
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What is a Mechanical Wave? |
A wave which requires movement of particles to propagate forward. This it requires a medium. It is one of the two major groups of waves. |
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What is an electromagnetic Wave? |
A wave that propagates as a perpendicular electric and magnetic field. They do not require a medium for propagation. It is the second major wave group. |
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What is an Oscillation? |
A vibration a fixed or equilibrium point. |
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Why do Electromagnetic Waves Travel Greater Ranges than Mechanical? |
Because they are not subject to the same energy losses due to friction between particles. |
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How are Mechanical Waves Classified? |
According to the direction of disturbance or vibration relative to the direction of energy flow through a material. |
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Describe a Transverse Wave |
The particles of the medium vibrate in a plane that is perpendicular to the direction of propagation of the wave |
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Describe a Longitudinal Wave |
the particles of the medium vibrate in the same direction as the direction of propagation of the wave. |
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Why are Electromagnetic Waves Transverse? |
Because they consist of alternating electric and magnetic force fields ninety degrees to one another and direction of energy propagation. |
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Define Compression |
A zone where the particles of the medium are pushed together. A higher pressure zone. |
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Define Rarefaction |
A zone where the particles of the medium are spread out. A lower pressure zone. |
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What are Sound Waves? |
The vibrations of particles in a medium. |
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What does Compression Relate to ? |
The Crests in a transverse wave. *(In terms of a longitudinal wave being represented as a transverse one) |
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What does Rarefaction Relate to? |
The Troughs of a transverse wave. *(In terms of a longitudinal wave being represented as a transverse one) |
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Describe what Pitch is |
It is directly related to the frequency of a sound. The higher the frequency, the more vibrations per second, and the higher the pitch. |
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What Determines how Loud a Sound Wave is? |
The higher the amplitude the louder the sound. |
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What is an Echo? |
The reflection of a sound wave. |
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What is Interference? |
The interaction of waves when they meet/ pass through each other, reinforcing (if waves waves are in phase) or cancelling( if waves are out of phase) at different points. |
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what is Superposition? |
Essentially the addition of waves. |
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What does the Principle of Superposition state? |
That if two or more waves of the same type pass through the same medium at the same time, then the amplitudes of the waves add together. It involves adding individual displacements at various points in a systematic way. |
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Define the term Beats |
It refers to the change in volume of a sound that occurs when two sounds of slightly different frequencies occur together. |
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How can Sound Waves be Studied? |
A cathode-ray oscilloscope simulator computer program. it allows us to view sound waves on a screen. |
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What is the Electromagnetic Spectrum? |
It is the full range of wavelengths of all electromagnetic wave. |
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What Speed do Electromagnetic Waves travel at ? |
At the speed of light. (3x10^8m/s^-1) |
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What Wave can Carry Information as Codes? |
Electromagnetic Waves. |
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How is the Electromagnetic Spectrum b? |
Through artificial divisions based on frequency and wavelengths, but there is no distinct point at which the frequency changes nor special point of change in properties at particular boundaries. |
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What Wave Types Make up the Spectrum? |
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How are EM Waves Represented? |
As sinusoidal or complex transversal waves. |
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What are Complex EM Waves? |
Like sound waves , they are made up of multiple simple waves superimposed. |
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What Happens when EM Waves Enter Different Mediums of Different Densities? |
They can be bent or refracted . |
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What Happens When You Go Further Up the Spectrum? |
* Energy increases * Frequency Increases * Wavelength decreases |
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Wavelengths of Radio Waves? |
They range from 10cm to 1000m |
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What are Radio Waves Used to Transmit? |
* Television * FM and AM radio * Radar and some mobile signals |
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What is the Wavelength of Microwaves? |
1 mm to 30 cm |
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What are Applications of Microwaves? |
The microwave oven. A frequency of 2450 MHz is emitted, which the water in food absorbs and becomes warmer due to the energy. |
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What is the Wavelength of Infra-red Waves? |
700nm to 1mm |
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What are Some Applications of Infra-red Waves? |
* Electronic remote Controls * Computer to computer data transfers * Checking for Hotspots |
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What is the Wavelength of Visible Light? |
400-700nm |
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What are Some Applications of Visible Light? |
* Fibre optic telecommunications * Aeroplane surveys * Identification of different objects |
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What is the Wavelength of Ultraviolet Light ? |
10-400nm |
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What are Some Applications of Ultraviolet Light? |
* To cure plastics * making astronomical observations * sterilising hospital equipment |
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What is the Wavelength of X-rays ? |
0.01 to 10nm |
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What are Some Applications of X-rays? |
* standard medical examinations * engineering to inspect welds for cracks * To predict space weather |
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What is the Wavelength of Gamma Rays? |
Less than 0.01nm |
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What are Some Applications of Gamma Rays? |
* some treatment of Cancers * Astronomical investigations |
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What is the Ionosphere? |
The layer of the earth's atmosphere which contains a high concentration of ions and free electrons and is able to reflect radio waves. It lies above the mesosphere and extends from about 80 to 1,000 km above the earth's surface. |
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How does the Ionosphere Benefit the Earth. |
It absorbs many waves, reducing them to be harmless, thus filtering out intense light such as x-rays and reducing the amount let in. |
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What is Attenuation ? |
The fall off energy that occurs as a wave passes through a medium. |
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State the Inverse Square Law |
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What is Light Measure in? |
Units called 'lux' (lx) * times 1/9 intensity by 16000 lux to get lux |
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What is Modulation? |
The process of changing the amplitude or frequency of a wave to add a signal/ information. |
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Define Bandwidth |
It describes a series of adjacent frequencies forming a band within the spectrum. |
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How is a Radio Wave Modulated ? |
Through the use of a carrier wave which does not carry any information (it is a by-product)but acts as a central frequency. The message signal is added to the carrier wave through superposition. |
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What is the Normal? |
The line that is perpendicular to the reflecting surface at the point where the ray hits. |
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What does the Law of Reflection State? |
The angle of the incoming, or incident, wave in relation to a line perpendicular to the reflecting surface (normal) is equal to the angle the reflected wave will make with the normal. |
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Summary of the Law of reflection |
The angle of incidence equals the angle of reflection. |
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When is Reflection Regular? |
When the wave is reflected from a flat surface. |
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When id Reflection Diffuse? |
When the wave is reflected from a bumpy or irregular surface. |
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Define Focus |
The point where all rays from a converging lens or the point where the rays appear to originate after passing through a diverging lens or being reflected by a diverging mirror. |
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What is Refraction? |
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