Definintions

Question 1

Centre of Mass

Answer 1

Point through which all the weight of an object is considered to act

Question 2

Moment

Answer 2

Force multiplied by the perpendicular distance from the line of action of the force to the pivot

Question 3

Couple

Answer 3

A pair of equal and opposite forces acting on a body but not along the same line (coplanar)

Question 4

Displacement

Answer 4

Distance in a given direction from a fixed point

Question 5

Velocity

Answer 5

Rate of change of displacement

Question 6

Acceleration

Answer 6

Rate of change of velocity

Question 7

Power

Answer 7

Rate of energy transfer/rate of doing work

Question 8

Force

Answer 8

Rate of change of momentum

Question 9

Impulse

Answer 9

Force x time for which the force acts
OR
change in momentum

Question 10

Amplitude

Answer 10

Maximum displacement from equilibrium position

Question 11

Frequency

Answer 11

Number of complete waves passing a point per unit time/per second

Question 12

Time Period

Answer 12

Time taken to complete one oscillation

Question 13

Wavelength

Answer 13

Distance between two identical positions on two adjacent waves

Question 14

Wave Speed

Answer 14

Product of a waves frequency and wavelength

Question 15

Phase

Answer 15

A measure of how far through the wave’s cycle a given point on the wave
is

Question 16

Phase Difference

Answer 16

Difference in phase between two points on a wave
(in angles or fractions of a cycle)

Question 17

Coherence

Answer 17

Same frequency/wavelength
Constant phase relationship

Question 18

Path difference

Answer 18

How far ahead a wave is compared to another wave

Question 19

Centripetal Force

Answer 19

Resultant force stopping a body from leaving the circle

Question 20

Restoring Force

Answer 20

Resultant force acting on an oscillating object towards equilibrium position.

Question 21

Resistance

Answer 21

Potential difference across a component per amp of current flowing through it.

Question 22

Potential Difference

Answer 22

Amount of energy transformed when one coulomb of charge is moved between two points
Work done per unit charge

Question 23

Current

Answer 23

Rate of flow of positive charge

Question 24

Superconductor

Answer 24

Material with 0 resistivity below critical temperature

Question 25

Critical Temperature

Answer 25

Temperature below which material becomes superconducting

Question 26

EMF

Answer 26

The amount of energy transferred from chemical energy to electrical energy per unit charge

Question 27

Terminal Potential Difference

Answer 27

Voltage across the terminals of a cell

Question 28

Ohmic Conductor

Answer 28

Any component that conducts electricity and obeys Ohm's law

Question 29

Potential Divider

Answer 29

A circuit that shares the potential difference between components by connecting multiple resistors in series

Question 30

Resistivity

Answer 30

How resistive a material is to allowing current to flow through it.

Question 31

Work function

Answer 31

Minimum energy required to liberate an electron form the surface of a metal.

Question 32

Photon

Answer 32

Small discrete packet of energy (no mass)

Question 33

Stopping potential

Answer 33

Minimum potential difference required for 0 current in a photocell circuit

Question 34

Electron volt

Answer 34

Energy gained by an electron as it accelerates through a potential difference of 1 volt

Question 35

Excitation

Answer 35

When an electron moves to a higher energy levelby absorbing energy from an incident photon or electron

Question 36

Ionistation

Answer 36

When an electron gains enough energy to leave the atom

Question 37

Threshold Frequency

Answer 37

Minimum frequency of a photon for a photoelectron to be emitted from a metal surface

Question 38

Elastic Behaviour

Answer 38

when a sample that has been deformed by a force returns to its original shape and size when the force causing the deformation is removed.

Question 39

Plastic Behaviour

Answer 39

when the deforming force is removed the material does not return to its original shape/size.

Question 40

Elastic Limit

Answer 40

maximum amount that a material can be stretched by a force, and still return to its original length when the force is removed

Question 41

Yield Point

Answer 41

point at which the material extends considerably with no (or a very small) increase in force. The extension is permanent.

Question 42

Ductile

Answer 42

easily and permanently stretched

Question 43

Brittle

Answer 43

fractures very soon after the elastic limit, with little or no plastic deformation. (e.g. concrete, glass)

Question 44

Potential divider

Answer 44

Circuit containing a combination of resistors in seriesacross a voltage source so that potential difference has been split

Question 45

Ionisation Energy

Answer 45

Minimum energy t remove an electron from an atom from the ground state