ALL DEFINITIONS PAPER 1

Question 1

System

Answer 1

An object or group of objects

Question 2

Kinetic energy

Answer 2

The energy of a moving object.

Question 3

Elastic potential energy

Answer 3

: The energy stored in a stretched spring (or another elastic object).

Question 4

Gravitational potential energy

Answer 4

The energy of an object due to its position in a gravitational
field.

Question 5

Specific heat capacity

Answer 5

The amount of energy required to raise the temperature of one
kilogram of a substance by one degree Celsius.

Question 6

Power

Answer 6

The rate at which energy is transferred or the rate at which work is done

Question 7

Conservation of energy

Answer 7

Energy can be transferred usefully, stored or dissipated, but cannot be
created or destroyed

Question 8

Dissipated energy

Answer 8

Energy that is stored in less useful ways, often described as being ‘wasted’

Question 9

Efficiency

Answer 9

The proportion of the total energy input that is transferred usefully.

Question 10

Renewable energy resource

Answer 10

: An energy resource that is being (or can be) replenished as it is
used

Question 11

Electric current:

Answer 11

A flow of electrical charge

Question 12

Potential difference (pd)

Answer 12

The work done per unit charge as the charge passes through a
component

Question 13

Thermistor

Answer 13

A resistor whose resistance changes with temperature

Question 14

Light-dependent resistor (LDR)

Answer 14

A resistor whose resistance changes with light intensity

Question 15

Series circuit:

Answer 15

A circuit where components are connected one after another in a single loop, so
the same current flows through each.

Question 16

Parallel circuit:

Answer 16

A circuit where components are connected in separate branches, so the current is shared between the branches and the potential difference across each component is the same.

Question 17

Direct current (dc):

Answer 17

An electric current that flows in one direction only

Question 18

Alternating current (ac)

Answer 18

: An electric current that repeatedly reverses its direction.

Question 19

Neutral wire:

Answer 19

: One of the wires in a mains electricity supply that completes the circuit and is at
or close to earth potential (0 V).

Question 20

Live wire

Answer 20

One of the wires in a mains electricity supply that carries the alternating potential
difference from the supply.

Question 21

Earth wire:

Answer 21

: A safety wire in a mains electricity supply that is at 0 V and only carries a current if
there is a fault.

Question 22

National Grid:

Answer 22

: A system of cables and transformers linking power stations to consumers.

Question 23

Electric field:

Answer 23

: A region around a charged object where another charged object experiences a
force.

Question 24

Density

Answer 24

The mass per unit volume of a material.

Question 25

Internal energy

Answer 25

The total kinetic energy and potential energy of all the particles that make up a system.

Question 26

Specific latent heat of fusion:

Answer 26

The energy required to change a substance from solid to liquid

Question 27

Specific latent heat of vaporisation

Answer 27

The energy required to change a substance from liquid to vapour

Question 28

Nucleus (of an atom):

Answer 28

The central part of an atom containing protons and neutrons

Question 29

Atomic number

Answer 29

The number of protons in the nucleus of an atom of an element.

Question 30

Mass number:

Answer 30

The total number of protons and neutrons in the nucleus of an atom

Question 31

Isotopes

Answer 31

Atoms of the same element that have different numbers of neutrons.

Question 32

Ion

Answer 32

An atom or molecule that has gained or lost one or more electrons, giving it an overall electric charge.

Question 33

Radioactive decay:

Answer 33

: The process by which unstable atomic nuclei spontaneously break down, emitting radiation

Question 34

Alpha particle (α):

Answer 34

: A type of radioactive emission consisting of two protons and two neutrons (a helium nucleus).

Question 35

Beta particle (β):

Answer 35

A high-speed electron ejected from the nucleus during radioactive decay.

Question 36

Gamma ray (γ)

Answer 36

: Electromagnetic radiation emitted from the nucleus during radioactive decay

Question 37

Half-life:

Answer 37

The time it takes for the number of nuclei of a radioactive isotope in a sample to halve, or the time it takes for the count rate to fall to half its initial level.

Question 38

Radioactive contamination:

Answer 38

The unwanted presence of materials containing radioactive atoms on other materials

Question 39

Irradiation

Answer 39

: The process of exposing an object to nuclear radiation; the object does not become radioactive

Question 40

Background radiation

Answer 40

Low-level radiation that is around us all the time from natural and manmade sources

Question 41

Nuclear fission:

Answer 41

The splitting of a large and unstable atomic nucleus

Question 42

Nuclear fusion

Answer 42

The process by which two light atomic nuclei join to form a heavier nucleus, releasing energy.