2.1 Electricity Key Terms

Question 1

Electrical Current

Answer 1

the rate of flow of charge

Question 2

Potential Difference

Answer 2

the work done as charge flows round a circuit

Question 3

Resistor

Answer 3

acts to limit the current in a circuit.

Question 4

Power

Answer 4

the rate of transfer of energy OR the rate at which work is done

Question 5

Transformer

Answer 5

a device that steps up or steps down the p.d.

Question 6

Electric Field

Answer 6

(similar to magnetic and gravitational fields) is created around a charged object and exerts a force on other charged objects

Question 7

Frequency

Answer 7

number of complete cycles per second

Question 8

Diode

Answer 8

A component in a circuit that allows current to flow in only one direction

Question 9

Light Dependent Resisitor (LDR)

Answer 9

A light controlled variable resistor

Question 10

Light Emitting Diode (LED)

Answer 10

A type of diode that lights up when current flows through it.

Question 11

Thermistor

Answer 11

An electrical resistor whose resistance is significantly reduced by heating

Question 12

Ohm’s Law

Answer 12

The current through a resistor is proportional to the p.d. and inversely proportional to the resistance

Question 13

Ohmic Resistor

Answer 13

Current is directly proportional to p.d.; resistance is constant

Question 14

Non-Ohmic Resistor

Answer 14

Current is not directly proportional to p.d. ; resistance changes with current

Question 15

Series Circuit

Answer 15

the same current flows through each component and the p.d. is shared across each component

Question 16

Parallel Circuit

Answer 16

the p.d. is the same across each branch and the total current is the sum of the current in each branch

Question 17

Direct Current

Answer 17

the current flows in one direction only

Question 18

Alternating Current

Answer 18

the direction of the current flow alternates

Question 19

National Grid

Answer 19

the distribution network for mains electricity

Question 20

Mains Electricity

Answer 20

230V, 50Hz, AC

Question 21

1 Ampere

Answer 21

1 Coulomb per second

Question 22

1 Volt

Answer 22

1 joule per coulomb

Question 23

I Watt

Answer 23

1 joule per second

Question 24

Charge flow

Answer 24

current * time

Question 25

potential difference

Answer 25

current * resistance

Question 26

power

Answer 26

potential difference * current
current squared * resistance

Question 27

energy transferred

Answer 27

power * time
charge flow * potential difference

Question 28

Series potential difference

Answer 28

V(supply) = V(1) + V(2)

Question 29

Series Resistance

Answer 29

R(total) = R(1) + R(2)

Question 30

Calibrate

Answer 30

mark a scale onto a measuring instrument, so that you can give a value to a measured quantity.

Question 31

Directly Proportional

Answer 31

As one amount increases, another amount increases at the same rate

Question 32

Extrapolation

Answer 32

To make an estimate (or prediction) assuming that an existing trend or pattern continues to apply in an unknown situation

Question 33

Interval

Answer 33

The difference between one value and the next in a set of data

Question 34

Inversely Proportional

Answer 34

As one amount increases, another amount decreases at the same rate. The product remains unchanged