Ocr As Physics

Front 1

Displacement

Back 1

The shortest distance from the initial position to the final position, in a particular direction.

Front 2

Average speed

Back 2

The distance travelled by an object divided by the duration of the time interval.

Front 3

Instantaneous speed –

Back 3

The limit of the average speed as the duration of the time interval tends towards zero.

Front 4

Velocity –

Back 4

The speed in one particular direction.

Front 5

Acceleration –

Back 5

The rate of change in velocity.

Front 6

Newton –

Back 6

The force that would be needed to give a mass of one kilogram an acceleration of one metre per second per second.

Front 7

Terminal velocity –

Back 7

The constant speed that a freely falling object eventually reaches when the resistance of the medium through which it is falling prevents further acceleration due to the system reaching an equilibrium of forces.

Front 8

Centre of Gravity –

Back 8

The point at which the entire weight of an object appears to act.

Front 9

Torque –

Back 9

A twisting force that tends to lead to rotation about an axis.

Front 10

Couple –

Back 10

When two forces, equal in size, act in opposite directions but not along the same straight line. There is no resultant force, but produces a turning effect.

Front 11

Equilibrium –

Back 11

The sum of the clockwise moments is equal to the sum of the anticlockwise moments; there is no resultant force.

Front 12

Thinking distance –

Back 12

The distance travelled by a vehicle between the time that it needs to brake is perceived and the time that the brakes are applied.

Front 13

Braking distance –

Back 13

The distance a vehicle will travel from the point where its brakes are fully applied to when it comes to a complete stop.

Front 14

Stopping distance –

Back 14

The total distance needed to perceive, react, and brake to a stop.

Front 15

Work done –

Back 15

The amount of energy transferred by a force acting through a distance.

Front 16

Joule –

Back 16

The work done by a force of one Newton through a distance of one metre in the direction of action of the force.

Front 17

Power–

Back 17

The rate of doing work.

Front 18

Watt –

Back 18

One Joule per second.

Front 19

Stress –

Back 19

The pressure or tension exerted on a material object.

Front 20

Strain –

Back 20

The magnitude of a deformation, equal to the change in the dimension of a deformed object divided by its original dimension.

Front 21

Young modulus –

Back 21

The ratio of stress over strain.

Front 22

Ultimate tensile strength –

Back 22

The maximum stress that a material can withstand before breaking.

Front 23

Elastic deformation –

Back 23

The part of the total strain in a stressed body that disappears upon removal of the stress.

Front 24

Plastic deformation–

Back 24

A permanent change in the shape or size of a solid body, without fracture, resulting from the application of sustained stress beyond the elastic limit.

Front 25

Coulomb –

Back 25

The amount of charge that flows in one seconds by a current of one ampere.

Front 26

Kirchhoff’s first law –

Back 26

At any point in a circuit, the sum of the currents flowing into that point is equal to the sum of the currents leaving that point.

Front 27

Kirchhoff’s second law–

Back 27

The sum of the E.M.Fs in any closed loop in a circuit is equal to the sum of the P.Ds across each component.

Front 28

Mean drift velocity –

Back 28

The average velocity that a particle, such as an electron, attains due to an electric field.

Front 29

Potential difference –

Back 29

The energy transferred per unit charge from electrical to other forms of energy.

Front 30

The volt–

Back 30

The difference in electrical potential energy that would carry one ampere of current against one ohm of resistance.

Front 31

Electromotive force –

Back 31

The energy transferred per unit charge from other forms of energy to electrical.

Front 32

Resistance –

Back 32

The ratio of potential difference across the component to the current through it; a material’s opposition to the flow of electric current.

Front 33

The Ohm–

Back 33

The resistance in a circuit transmitting a current of one ampere when subjected to a potential difference of one volt.

Front 34

Ohm’s law –

Back 34

The current in a wire is directly proportional to voltage across it, as long as the temperature of the wire remains constant.

Front 35

Resistivity –

Back 35

A measure of the resistance of a material to the flow of an electric current, per unit length for a uniform cross-section.

Front 36

The kilowatt-hour –

Back 36

A measure of electrical energy equivalent to a power consumption of 1,000 watts for one hour.

Front 37

Displacement –

Back 37

The distance moved by a single point on a wave, relative to its rest position.

Front 38

Amplitude –

Back 38

The waves maximum displacement.

Front 39

Wavelength –

Back 39

The distance between two successive points on a wave with equivalent displacements.

Front 40

Period –

Back 40

The time taken for a wave to oscillate once.

Front 41

Phasedifference–

Back 41

The relationship, in time, between the successive states of an oscillating wave and either a fixed reference point, or the successive states of another oscillating wave.

Front 42

Frequency –

Back 42

The rate of oscillation of a wave.

Front 43

Wave speed –

Back 43

The average distance a progressive wave travels in one second.

Front 44

Plane polarisation –

Back 44

The oscillation of a wave in a single plane.

Front 45

Malus’s law –

Back 45

When a perfect polariser is placed in a polarised beam of light, the intensity, l, of the light that passes through is given by,

I=I_0 cos^2⁡〖θ_i 〗

Front 46

Interference –

Back 46

The combination of two or more waves to form a resultant wave in which the displacement is either reinforced or cancelled.

Front 47

Coherence–

Back 47

Waves having the same direction, wavelength and phase relation

Front 48

Path difference–

Back 48

The difference, in meters, of the distance travelled by two monochromatic waves.

Front 49

Nodes –

Back 49

The point at which there is zero displacement in a standing wave system.

Front 50

Antinode –

Back 50

The point at which there is maximum displacement in a standing wave system.

Front 51

Fundamental mode of vibration –

Back 51

The lowest frequency at which an oscillation can occur.

Front 52

Harmonics–

Back 52

The frequencies of a wave that are integer multiples of it’s fundamental frequency.

Front 53

The electronvolt –

Back 53

The unit of energy equal to the work done on an electron in accelerating it through a potential difference of one volt.

Front 54

Work function –

Back 54

The minimum quantity of energy that is required to remove an electron to infinity from the surface of a given solid, usually a metal.

Front 55

Threshold frequency –

Back 55

The lowest frequency of electromagnetic radiation that will result in the emission of photoelectrons from a specified metal surface.