Electricity key terms

Question 1

Electric Charge = Coulomb

Answer 1

Measurement of the amount of charge in any situation

Question 2

Earthing

Answer 2

When an object becomes charged and then ‘earthed’ by connecting to the earth , the electrons will seperate as much as possible , resulting in most of them ‘going to earth ‘

Question 3

Insulator

Answer 3

Any substance through which an electric charge cannot flow

Question 4

Conductor

Answer 4

A medium that allows electric charge to flow easily through it.

Question 5

Coulomb’s law (1)

Answer 5

States that the force between two point charges is proportional to the product of the charges and inversely proportional to the square of the distance between them

Question 6

Coulomb’s law (2)

Answer 6

A static charge will exert a force of attraction or repulsion on another static charge in its vicinity

Question 7

Forces between charges

Answer 7

There is an electric force between all charged particles

Question 8

Ions

Answer 8

Atoms with an overall charge

Question 9

Positive ion

Answer 9

Losing e’s

Question 10

Negative ion

Answer 10

Gain an electron

Question 11

Polythene rod

Answer 11

Insulator
Rub with cloth to become charged negatively

Question 12

Perspex rod

Answer 12

Conductor
Rub with a cloth and becomes positively charged

Question 13

Different ways of charging bodies

Answer 13

Friction, rub rod with cloth
Contact , two conductors spread charge evenly by contact
Induction , put negatively charged rod close to a metal sphere free electrons are pushed to left hand side and some negative electrons leave sphere causing electrons to be positive

Question 14

Static electricity in real life

Answer 14

Dust on tv screens
Static charge on clothes

Question 15

Inducing charges

Answer 15

Move negative / positive rod close to
Earth metal subject
Remove earth
Remove rod

Question 16

Insulator

Answer 16

A medium that does not allow electric charge to flow easily through it.

Question 17

Electric field lines

Answer 17

Show the direction and strength of a force due to a positive charge in the field

Question 18

Electric field strength

Answer 18

The force that a 1 coulomb charge would experience at a point in an electric field.

Question 19

Potential difference / voltage (V) (v)

Answer 19

The work required to move a charge of 1 coulomb from 1 point to another.
 Unless specified the second point is ground.

Question 20

Electromotive Force EMF (E) (v)

Answer 20

Similar to voltage but created by induction.

Question 21

Capacitor

Answer 21

A device capable of storing an electrical charge.

Question 22

Current (I) (A)

Answer 22

A flow of charge though a conductor
 Electrons, Ions, Holes

Question 23

Series

Answer 23

A circuit where there is no split.

Question 24

Parallel circuit

Answer 24

A circuit where there is a split.

Question 25

Resistance (R) (Ω)

Answer 25

The ratio of potential difference across an object to the current flowing through it.

Question 26

Potential divider

Answer 26

A circuit structure that divides a voltage between 2 sub circuits

Question 27

Resistivity

Answer 27

The potential a material has for resistance Length Cross sectional area Material

Question 28

Wheatstone bridge

Answer 28

A circuit used to find the value of an unknown resistor via ratios Meter bridge

Question 29

Semi conductors

Answer 29

Materials that have a resistivity that is between a good conductor and good insulator

Question 30

Semiconductor conduction intrinsic

Answer 30

Intrinsic  Conduction due to electrons and holes in a pure semiconductor material

Question 31

Semiconductor conduction extrinsic

Answer 31

Increased conductivity due to the controlled addition of impurities

Question 32

Semiconductor doping

Answer 32

The controlled addition of impurities to a semiconductor to increase conductivity

Question 33

Semiconductor p-type

Answer 33

Silicon with doped boron to increase the amount of holes in the semiconductor. There is a surplus of free positive charges carrying particles yet charge is still 0

Question 34

Semiconductor n-type

Answer 34

Silicon with doled phosphorus to increase the amount of free electrons in the semiconductor. There is a surplus of free negative charge carrying particles , yet the net charge is still 0

Question 35

P-N junction

Answer 35

When a p and n semiconductor join they from a single semiconductor that allows charge to flow in one direction

Question 36

Depletion layer

Answer 36

The region in the middle of a p-n junction that is almost void of charge carrying particles due to a voltage being created

Question 37

1 ampere

Answer 37

1 amp is the constant current when 2 straight infinitely long parallel conductors are 1 meter apart, in a vacuum, with negligible cross-sectional area; experience a force between them of 2 𝑥 10−7 N/m.

Question 38

Magnetic flux (Φ) (Wb)

Answer 38

Number of magnetic field lines passing through a surface.

Question 39

Electromagnetic induction

Answer 39

When a change in magnetic field creates an EMF in a conductor which in turn produces a current

Question 40

Mutual induction

Answer 40

 A change in magnetic field in 1 coil produces an EMF in another adjacent coil.

Question 41

Self induction

Answer 41

 A change in magnetic field in 1 coil produces a back EMF in itself.

Question 42

Joules law

Answer 42

Power is inversely proportional to the current squared provided resistance is constant

Question 43

rms

Answer 43

Root mean squared The rms voltage is the equivalent DC voltage that would produce the same power dissipation in a resistor. For AC voltages, it represents the effective voltage.

Question 44

What is meant by a.c

Answer 44

(Alternating Current): A current that periodically changes direction, typically sinusoidal in household electricity.