# Physics Unit

What does the term oscillation mean ?
It can be defined as a regularly repeating motion for around a central value.
1 of 51
How do you define frequency ?
It can be shown as the number of whole cycles occurring in one second.
2 of 51
What is the term period ?
It is the time taken for one whole cycle of an oscillation, this is before the motion starts to repeat itself.
3 of 51
What is the term displacement ?
This is how far the quantity that is in the oscillation has moved from the mean under the rest value at any given time.
4 of 51
What is the term amplitude ?
It can be defined as the maximum displacement in an oscillation cycle which is always measured from the mean position.
5 of 51
What is the term wavelength ?
This is known as the distance along the wave in its direction of travel between consecutive points where the oscillations are in phase.
6 of 51
What is the term phase difference ?
This is the difference in phase angles between two waves of the same frequency and wavelength, where 360 degrees represent a single whole cycle of the waveform.
7 of 51
Define a transverse wave
A transverse wave is where the direction of the particles of the medium move perpendicularly to the direction as that of the wave.
8 of 51
Define a longitudinal wave
A longitudinal wave is where the direction of the particles of the medium move in the same direction as that of the wave.
9 of 51
What is the term diffraction ?
It can be defined as the tendency of a wave which has been spread out in all directions, transferring energy in its surroundings.
10 of 51
What happens after the diffraction ?
The energy is being transferred to its surroundings.
11 of 51
What is a diffraction grating ?
It is a flat plane object . It has series of regular lines formed on it that block parts of an advancing wavefront.
12 of 51
What happens when a wave hits a surface ?
The wavefront reflects or gets absorb into the material.
13 of 51
What happens when a wave goes through a gap ?
Waves energy passes travels around the gap.
14 of 51
What can you see when diffraction occurs ?
The wavefront that pass through the gap allows the wave energy to move forward and some of. It spreads around in other direction.
15 of 51
What does the term transmission mean ?
It shows how wave energy passing through an object such as the diffraction grating and this will mostly continue forward in the original direction where some energy will be diffracted through angles less than 90 degrees.
16 of 51
Define reflection ?
It can be shown as the wave energy which bounces off a surface and has the direction to travel as being altered by more than 180 degrees.
17 of 51
What is interference pattern ?
It is caused by a stationary pattern that is caused from superposition of waves that travel in different directions, they are known as to be coherent.
18 of 51
What is superposition ?
Adding another wave of displacement that occurs when waves from more individual sources overlap at any location of space.
19 of 51
What can superposition also cause ?
A stationary wave when two waves with different phase collide with each other.
20 of 51
What is coherent ?
It can be defined as sticking together and is described for waves that superposition gives a visible interference pattern.
21 of 51
What must happen so that waves can be coherent ?
They need to have the same frequency, same wavelength and have and constant phase difference.
22 of 51
Define photon ?
It is a quantum of electromagnetic radiation where photons have zero mass and zero charge, but definite energy value linked to their frequency.
23 of 51
What is the term quantum ?
It can be known as the smallest unit that can exists independently where it has clearly defined the values of energy, mass, charge and other physical quantities.
24 of 51
What is the quantum theory ?
It combines ideas from the use if wave motions and particle mechanics theories in order to create new wave mechanics.
25 of 51
Define the energy level ?
It is one of the fixated, allowed values of energy for an electron which is in bound in an atom.
26 of 51
Define ground state ?
It can be known as the lowest energy state possible for a given bound particle.
27 of 51
What are stationary waves ?
These are wave motions which store energy rather than transferring energy to other locations.
28 of 51
Define node ?
This points along the stationary wave where the displacement amplitude that occur halfway between each pair of nodes.
29 of 51
Define antinode ?
This can point out the maximum amplitude that occurs halfway between each pair of the nodes.
30 of 51
What is resonance ?
It is the storing of energy in an oscillation or perhaps a stationary wave, the energy coming from the external source of appropriately matched frequency.
31 of 51
Define forcing frequency ?
It is the frequency of wave energy that is from an external source that is coupled to a resonator.
32 of 51
Define natural frequency ?
It is a resonator which has a series or even natural frequencies which corresponds to an exact number of half wavelengths fitting in the boundaries.
33 of 51
Define refractive index ?
It is the transparent medium where the ratio of the speed of light in a vacuum is aligned to the medium.
34 of 51
Define the normal line ?
It is a line at the right angles to the surface of a transparent medium that passes through a point where the ray enters or even exists in that medium.
35 of 51
Define incidence ?
It is the direction of an incoming ray.
36 of 51
Define refraction ?
It can be shown as the bending of the direction of travel so it can describe the direction of an outgoing ray after bending.
37 of 51
What is the term internal reflection ?
It is when a wave is already in a dense medium when it hits the boundary with a less or even dense medium where the energy has been reflected back to a denser medium.
38 of 51
Define critical angle ?
It can be presented as when a ray in a medium with a higher refractive index hits the boundary with a less dense medium, this is where the angle of incidence where the refracted ray would be at 90 degrees.
39 of 51
Define total internal reflection ?
It is when all wave energy is internally reflected and none is lost as a refracted ray and this happens for all angles in incidence larger than the critical angle.
40 of 51
What are analogue signals ?
A signal with the strength proportional to the quantity that it is representing.
41 of 51
What are digital signals ?
A signal which conveys a binary code which is a number that represents the size of that measured quantity.
42 of 51
Define the electromagnetic spectrum ?
The complete range of electromagnetic waves placed in order of increasing frequency.
43 of 51
Electromagnetic waves with the longest wavelengths and lowest frequencies, used for communications.
44 of 51
Define microwaves ?
Electromagnetic waves that have shorter wavelengths and higher frequencies than radio waves, used for mobile phones, satellite communications and cooking.
45 of 51
Define infra-red ?
Used for thermal imaging and heat transfer by radiation.
46 of 51
Define visible light ?
Electromagnetic waves that you can see.
47 of 51
Define ultra-violet waves ?
Used for sterilizing medical equipment, detecting forgeries and causing sun burn.
48 of 51
Define x-rays ?
Used to see inside the body.
49 of 51
Define gamma rays ?
Used for sterilizing medical equipment, treating cancer in radiotherapy.
50 of 51
Define optical fibres ?
It can be known as a thin flexible fibre with a glass core through which light signals can be sent with very little loss of strength.
51 of 51

## Other cards in this set

### Card 2

#### Front

How do you define frequency ?

#### Back

It can be shown as the number of whole cycles occurring in one second.

### Card 3

#### Front

What is the term period ?

#### Back ### Card 4

#### Front

What is the term displacement ?

#### Back ### Card 5

#### Front

What is the term amplitude ?

#### Back 