Definitions for Electrons, Waves and Photons Flashcards
(ELECTRONS)
Define the Coulomb.
One Coulomb (C) is defined as the amount of charge that passes in 1 second when the current is 1 ampere.
Define Current.
Current is the rate of flow of charge.
Define Drift velocity.
The drift velocity is the average velocity of the electrons.
Define Potential difference.
Potential difference is the energy per unit charge.
Define the Volt.
The potential difference across a component is 1 volt when you convert 1 joule of energy moving 1 coulomb of charge through the component.
Define the Ohm.
A component has a resistance of 1 Ohm if a potential difference of 1 V makes a current of 1 A flow through it.
Define Power.
Power is defined as the rate of transfer of energy.
Define the Watt.
1 Watt is 1 Joule per second.
Define 1 Kilowatt-Hour. (kWh)
1 kWh is one unit of electricity. It is equal to 3.6 million Joules.
Define e.m.f
What is it measured in?
The amount of electrical energy the battery produces for each coulomb of charge is called its electromotive force (e.m.f).
e.m.f is measured in Volts.
Define terminal p.d.
The terminal p.d is the energy transferred when 1 coulomb of charge flows through the load resistance (total resistance of all components other than the battery).
Define ‘lost volts’.
The lost volts are the energy wasted per coulomb overcoming the internal resistance.
What is Kirchhoff’s first law?
Kirchhoff’s first law states that:
The total current entering a junction is equal to the total current leaving the junction.
What is Kirchhoff’s second law?
Kirchoff’s second law states that:
The total e.m.f. around a series circuit is equal to the sum of the p.d.s across each component.
(WAVES)
Define displacement.
Displacement is how far a point on the wave has moved from equilibrium.
Define amplitude.
Amplitude is the maximum displacement from equilibrium.
Define wavelength.
The length of one whole wave from crest to crest or trough to trough.
Define period.
The time taken for a whole vibration.
Define frequency.
The number of vibrations per second passing a given point.
Define phase difference.
The amount by which one wave lags behind another wave.
Define reflection.
Reflection is where the wave is bounced back when it hits a boundary.
Define refraction.
Refraction is where the wave changes direction as it enters a different medium, due to a change in speed while passing through the medium.
Define intensity.
Intensity is the rate of flow of energy per unit area at right angles to the direction of travel of the wave.
What is a transverse wave?
In transverse waves, the vibration is at right angles to the direction of travel.
What is a longitudinal wave?
In longitudinal waves, the vibrations are along the direction of travel.
What is a polarised wave?
A polarised wave only oscillates in one direction.
Define superposition.
Superposition happens when two or more waves pass through At that instant, the displacements due to each wave combine.
Define constructive interference.
Constructive interference is where the two interfering waves cause a bigger crest/trough.
Define destructive interference.
Destructive interference is where
