P2 - Electricity

Question 1

Alternating Potential Difference

Answer 1

A continually oscillating current flow, which
results in the potential difference across two points continually oscillating between
a positive and negative value.

Question 2

Amperes (Amps)

Answer 2

The unit of current

Question 3

Attraction

Answer 3

A force pulling two opposite charges together, when they are brought
near each other.

Question 4

Coulomb

Answer 4

The unit of charge.

Question 5

Diode

Answer 5

A component that only allows current to flow through in the forward
direction. They have very large resistances in the reverse direction.

Question 6

Direct Potential Difference

Answer 6

A one-directional current flow

Question 7

Earth Wire

Answer 7

The green and yellow striped safety wire that prevents an appliance
from becoming live.

Question 8

Electric Field Lines

Answer 8

Lines representing an electric field, that point in the
direction in which a positive charge would experience an electric force.

Question 9

Electric Field

Answer 9

A region in which a charge will experience a non-contact, electric
force. All charged objects have an electric field around them, and this field is
stronger the closer you are to the charge.

Question 10

Electrical Current

Answer 10

The rate of flow of electrical charge. Its value is the same at
any position in a single closed loop.

Question 11

Filament Lamp

Answer 11

A light emitting component consisting of an enclosed metal
filament. Its resistance increases as the filament’s temperature increases.

Question 12

Insulation

Answer 12

The coating around power cables that prevents electrocution and is
colour coded to allow for easy identification.

Question 13

Light Dependent Resistor (LDR)

Answer 13

A light sensitive component whose resistance
increases as its temperature decreases.

Question 14

Light Dependent Resistor (LDR)

Answer 14

A light sensitive component whose resistance
increases as its temperature decreases.

Question 15

Live Wire

Answer 15

The brown coloured wire that carries the alternating current from the
supply in a mains power supply.

Question 16

Mains Electricity

Answer 16

An a.c supply, which in the UK has a frequency of 50Hz a
value of 230V.

Question 17

Neutral Wire

Answer 17

The blue coloured wire that completes the circuit in a mains power
supply.

Question 18

Non-Contact Force

Answer 18

A force experienced between two separated objects.
Examples include gravity, and magnetic and electric forces.

Question 19

Ohmic Conductor

Answer 19

A conductor whose current flow is directly proportional to the
potential difference across it, when held at a constant temperature.

Question 20

Ohms

Answer 20

The unit of resistance.

Question 21

Parallel

Answer 21

Components connected in parallel have the same potential difference
across each component. The total current is equal to the sum of the currents
flowing through each component.

Question 22

Repulsion

Answer 22

Caused when two like-charges are brought near each other.

Question 23

Resistance

Answer 23

A measure of the opposition to current flow.

Question 24

Resistors in Parallel

Answer 24

The total resistance is equal to the inverse of the sum of
the inverses of the resistance of the parallel components. The total resistance of
two parallel resistors is always less than the lowest individual resistor value.

Question 25

Resistors in Series

Answer 25

The total resistance is equal to the sum of the resistances of
the individual components.

Question 26

Series

Answer 26

Components connected in series have the same current passing through
each component but share the total potential difference of the power supply.

Question 27

Static Charge

Answer 27

The charge caused by an imbalance of positive and negative
charges in, or on, an object’s surface. It is often caused by electrons being rubbed
from one surface onto another.

Question 28

Step-Down Transformers

Answer 28

Devices found between the transmission cables and
the consumer that lower the potential difference of the power so it is at safe,
usable levels.

Question 29

Step-Up Transformers

Answer 29

Devices that increase the potential difference generated
by a power station, so that the electrical power transmitted along the transmission
cables is at a higher potential.

Question 30

The National Grid

Answer 30

The network of power stations, transformers and cables that
connect consumers to power stations.

Question 31

Thermistor

Answer 31

A temperature dependent component, whose resistance increases
as its temperature decreases.