Definitions for Electrons, Waves and Photons

Question 1

(ELECTRONS)

Define the Coulomb.

Answer 1

One Coulomb (C) is defined as the amount of charge that passes in 1 second when the current is 1 ampere.

Question 2

Define Current.

Answer 2

Current is the rate of flow of charge.

Question 3

Define Drift velocity.

Answer 3

The drift velocity is the average velocity of the electrons.

Question 4

Define Potential difference.

Answer 4

Potential difference is the energy per unit charge.

Question 5

Define the Volt.

Answer 5

The potential difference across a component is 1 volt when you convert 1 joule of energy moving 1 coulomb of charge through the component.

Question 6

Define the Ohm.

Answer 6

A component has a resistance of 1 Ohm if a potential difference of 1 V makes a current of 1 A flow through it.

Question 7

Define Power.

Answer 7

Power is defined as the rate of transfer of energy.

Question 8

Define the Watt.

Answer 8

1 Watt is 1 Joule per second.

Question 9

Define 1 Kilowatt-Hour. (kWh)

Answer 9

1 kWh is one unit of electricity. It is equal to 3.6 million Joules.

Question 10

Define e.m.f

What is it measured in?

Answer 10

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.

Question 11

Define terminal p.d.

Answer 11

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).

Question 12

Define ‘lost volts’.

Answer 12

The lost volts are the energy wasted per coulomb overcoming the internal resistance.

Question 13

What is Kirchhoff’s first law?

Answer 13

Kirchhoff’s first law states that:

The total current entering a junction is equal to the total current leaving the junction.

Question 14

What is Kirchhoff’s second law?

Answer 14

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.

Question 15

(WAVES)

Define displacement.

Answer 15

Displacement is how far a point on the wave has moved from equilibrium.

Question 16

Define amplitude.

Answer 16

Amplitude is the maximum displacement from equilibrium.

Question 17

Define wavelength.

Answer 17

The length of one whole wave from crest to crest or trough to trough.

Question 18

Define period.

Answer 18

The time taken for a whole vibration.

Question 19

Define frequency.

Answer 19

The number of vibrations per second passing a given point.

Question 20

Define phase difference.

Answer 20

The amount by which one wave lags behind another wave.

Question 21

Define reflection.

Answer 21

Reflection is where the wave is bounced back when it hits a boundary.

Question 22

Define refraction.

Answer 22

Refraction is where the wave changes direction as it enters a different medium, due to a change in speed while passing through the medium.

Question 23

Define intensity.

Answer 23

Intensity is the rate of flow of energy per unit area at right angles to the direction of travel of the wave.

Question 24

What is a transverse wave?

Answer 24

In transverse waves, the vibration is at right angles to the direction of travel.

Question 25

What is a longitudinal wave?

Answer 25

In longitudinal waves, the vibrations are along the direction of travel.

Question 26

What is a polarised wave?

Answer 26

A polarised wave only oscillates in one direction.

Question 27

Define superposition.

Answer 27

Superposition happens when two or more waves pass through At that instant, the displacements due to each wave combine.

Question 28

Define constructive interference.

Answer 28

Constructive interference is where the two interfering waves cause a bigger crest/trough.

Question 29

Define destructive interference.

Answer 29

Destructive interference is where