Physics Flashcards
What is a progresive wave?
A wave that transports energy from one place to another
Where is the amplitude on a wave?
The amplitude is the distance from rest to crest.
Where is the wave length on a wave?
The distance between a point on one wave and the same point on the next wave.
For example, peak to peak.
What is the frequency?
Amount of waves per second
What does v=fλ mean?
Wave speed (v) is measured in metres per second (m/s) Frequency (f) is measured in Hertz (Hz) wavelength (λ) is measured in metres (m)
Wavespeed= Frequency x Wavelength
How do you calculate frequency from Time
Frequency=1 / T
Define isotope
Isotopes are atoms of an element with different numbers of neutrons
What is a longitudinal wave?
- The medium moves in the same direction of the wave
- It acts in one dimension
- It is made of rarefactions and compressions
What is a transverse wave?
- The medium is moving perpendicular to the direction of wave. At 90°
- It acts in two dimensions
- It is made of troughs and crests
What is phase difference?
The difference in phase angle between two waves of the same frequency and wavelength, where 360° represents a single whole cycle of the wave form.
How many radians are in 360°?
6
What is 360° convert to in terms of radians?
2 π Radians
What must be the same be for phase difference to happen?
Wavelength and frequency
What are coherant waves?
Waves that are in phase
What is the equation for photon energy?
E=HF
Energy= Plancks constant x Frequency
What is the ground state?
The lowest energy state of an electron
What is the energy level of an electron?
One of the fixed values of energy for an electron that is bound to an atom.
What is light made up of?
Packs of energy called photons.
What is the equation to work out N lambda?
n λ = d sin θ
n lambda = d sin theta
What is the definition for frequency?
F=1/T
What is the displacement?
How far the quantity that is in oscillation has moved from its mean
What is the oscillation
A regularly repeating motion about a central value
What is a period
The time taken for one whole cycle of an oscillation
How do you work out wave speed?
V=Fxlambda
What is frequency measured in?
Hertz (H)
Give an example of a longitudinal and transverse wave
Sound waves and water ripples
What is diffraction?
The tendency of a wave to spread out in all directions
What is a diffraction grating?
Flat plane object with a series of regular lines that blocks parts of an advancing wave front
What is transmission?
When some of the waves energy continues propagating forward through the gaps between the grating lines
What is superposition?
The adding together of wave displacements that occurs when two waves overlap
What is path difference?
The difference in length between two rays
What is the interference pattern?
A stationary pattern that can result from the superposition of waves travelling in different directions
Define coherent
Used to describe waves whose superposition gives a visible interference pattern
Explain the gratings in reflection mode in the diffraction grating
- You look at the part of the wave energy that is bounced back off the surface
- The grating lines are regularly spaced so an interference pattern is produced
What is a stationary wave?
When energy is stored rather than transferred
What is resonance
The storing of energy in an oscillation or a stationary wave
What is a node?
Points of minimum amplitude
What is an antinode?
Points if maximum amplitude
What is resonance
When the wave energy coming in from outside has a forcing frequency equal to the natural frequency of the resonator
What is the refractive index?
N=C/V
Index of refraction= Speed of light in vacuum/ Speed of light in medium
What is the critical angle?
When the angle of refraction is equal to 90 degrees.
What is total internal reflection?
When the angle of incidence is greater than the critical angle, the light cannot pass through the surface- it is all reflected.
What is the angle of incidence?
The angle between the normal and the ray of light.
What is an optical fibre?
A thin flexible fibre with a glass core through which light signals can be sent with very little loss of strength.
What is an endoscope?
Optical instruments with long tubes that can be inserted into the body through an opening. Used during keyhole surgery.
What are the 2 types of signals?
Analogue and digital
What is an analogue signal?
A signal whose strength is proportional to the quantity it is representing
What is a digital signal?
A digital signal is a signal that represents data as a sequence of discrete values.
It is possible to send data much faster than an analogue signal.
Define broadband
Used as a relative term to indicate the speed and carrying capacity if a data channel.
Define broadband
Used as a relative term to indicate the speed and carrying capacity if a data channel.
What is multimode fibre?
The standard fibre cable used for sending optical signals over short to medim distances.
What is single mode fibre?
Has a more narrower core, light moves as a single wave front straight down the centre of the fibre. Used for long distance
What is the speed of light?
3x10 to the power of 8
What is the only frequency that the naked eye can see?
Visible light
