Electricity and Magnetism Definitions

Question 1

Conductors

Answer 1

materials that let electrons pass through them

Question 2

Insulators

Answer 2

materials that hardly conduct(let electrons pass through) at all

Question 3

Semi-conductors

Answer 3

materials that are poor conductors when cold but better conductors when warm

Question 4

Earthing

Answer 4

the process of connecting an electrical device to the ground(so that unwanted charge goes away)

Question 5

Induced magnetism

Answer 5

a term used to describe the process in which a material can be turned into a magnet when it is put inside the magnetic field of any magnet

Question 6

Current

Answer 6

the amount of charge passing a point in a circuit every second

Question 7

Potential difference(voltage)

Answer 7

the energy transferred per coulomb of charge

Question 8

Resistance

Answer 8

opposition to current

Question 9

Resistors

Answer 9

electrical components that limit the passage of electrical current(provide resistance)

Question 10

Variable resistor(rheostats)

Answer 10

A resistor whose resistance can be changed manually

Question 11

Thermistors

Answer 11

resistors that have a high resistance when cold but a much lower resistance when hot(contain semiconductor materials)

Question 12

Light-dependent resistors(LDRs)

Answer 12

resistors that have a high resistance in the dark but a low resistance in the light

Question 13

Diodes

Answer 13

resistors that have an extremely high resistance in one direction but a low resistance in the other(allowing current to flow in one direction only)

Question 14

Power

Answer 14

the rate at which energy is transformed

Question 15

Alternating current

Answer 15

an electrical current that reverses its direction(many times a second) at regular intervals

Question 16

Direct current

Answer 16

an electrical current that flows in one direction only

Question 17

Magnetic field

Answer 17

a region in which a magnetic pole experiences a force

Question 18

Electric field

Answer 18

a region in which an electric charge experiences a force

Question 19

Electromotive force(e.m.f.)

Answer 19

the electrical work done by a source in moving a unit charge around a complete circuit

Question 20

Magnetic material

Answer 20

a material that can be magnetized and is attracted to magnets

Question 21

Hard magnetic materials

Answer 21

magnetic materials that are difficult to magnetize but do not readily lose their magnetism

Question 22

Soft magnetic materials

Answer 22

magnetic materials that are relatively easy to magnetize but are only magnetized temporarily

Question 23

Solenoid

Answer 23

a cylindrical coil of wire that acts as a magnet when carrying electrical current

Question 24

Magnetic relay

Answer 24

a switch operated by an electromagnet

Question 25

Circuit breaker

Answer 25

an automatic switch which cuts of the current in a circuit if it rises above a specific value

Question 26

Transformer

Answer 26

a device which increases or decreases the a.c. voltage of a power source

Question 27

Step-up transformer

Answer 27

a device which increases the potential difference of a power source

Question 28

Step-down transformer

Answer 28

a device which decreases the potential difference of a power source