Electricity

Question 1

Conductor

Answer 1

Any substance through which charge can flow

Question 2

Insulator

Answer 2

A substance through which electric charge cannot flow

Question 3

Coulomb’s Law

Answer 3

Force of attraction or repulsion between two point charges is directly proportional to the product of the charges and inversely proportional to the distance between them

Question 4

Electric Field

Answer 4

Any region of space where a static electric charge experiences a force other than the force of gravity

Question 5

Electric Field Strength

Answer 5

A point in an electric field is the force per unit charge at that point

Question 6

Potential Difference

Answer 6

(Between two points in electric field) the work done in bringing a charge of +1C from one point to the other

Question 7

Electric Current

Answer 7

Flow of electric charge

Question 8

Capacitance

Answer 8

(Of a conductor) the ratio of charge of the conductor to its potential

Question 9

Size of an Electric Current

Answer 9

Amount of charge passing any point of that conductor per second

Question 10

Ampere

Answer 10

Coulomb per second

Question 11

EMF

Answer 11

Voltage when applied to a circuit

Question 12

Resistance

Answer 12

(Of a conductor) the ratio of potential difference across it to the current flowing through it

Question 13

Joule’s Law

Answer 13

The rate at which heat is produced in a conduit is directly proportional to the square of the current provided it’s resistance is constant

Question 14

Fuse

Answer 14

A piece of wire that will melt when a current of a certain size passes through it

Question 15

MCB’s

Answer 15

Bimetallic strip and electromagnet which separate and break the circuit when current is larger than a certain value

Question 16

RCD’s

Answer 16

Detect the difference between current in the live and the neutral

Question 17

Semiconductor

Answer 17

Substance whose resistance is between that of a good conductor and a good insulator. The resistivity of a semiconductor decreases as temperature increases

Question 18

Intrinsic Conduction

Answer 18

Conduction in a pure semiconductor due to electrons moving from negative to positive and an equal number of holes moving in the opposite direction

Question 19

Extrinsic Conduction

Answer 19

Increased conduction in a semiconductor due to the addition of impurities

Question 20

Doping

Answer 20

Adding of small controlled amounts of certain impurities to a pure semiconductor to increase its conductivity

Question 21

N type Semiconductors

Answer 21

Those in which the impurity added produces more free electrons available for conduction

Question 22

P type Semiconductors

Answer 22

Those in which the impurity added produces extra holes which are available for conduction

Question 23

P-N Junction

Answer 23

A piece of semiconductor with a part of it doped p type and the other part doped n type

Question 24

Depletion Layer

Answer 24

The region at both sides of a p-n junction that contains no free majority charge carriers. Thus behaves as an insulator

Question 25

Junction Voltage

Answer 25

Potential difference that exists across a p-n junction caused by holes and electrons moving across the junction when it was formed

Question 26

Rectification

Answer 26

The conversion of a.c. to d.c.