Physics As Glossary E-K

Front 1

Efficiency

Back 1

The ratio of useful energy transferred (or the useful work done) by a machine or device to the energy supplied to it.

The ratio of the machines outward power to it's input power

Front 2

Effort

Back 2

The force applied to a machine to make it move

Front 3

Elastic limit

Back 3

Point beyond which a wire is permanently stretched

Front 4

Elasticity

Back 4

Property of a solid that enables it to regain its shape after it has been deformed or distorted

Front 5

Electrolysis

Back 5

Process of electric conduction in a solution or molten compound due to ions moving to the opposite charged electrode

Front 6

Electrolyte

Back 6

A solution or molten compound that conducts electricity

Front 7

Electromagnetic interaction (or force)

Back 7

Interaction (or force) between two charged objects

Front 8

Electromagnetic wave

Back 8

A wavepacket or photon consisting of transverse electric and magnetic waves in phase and at right angles to each other

Front 9

Electromotive force (emf)

Back 9

The amount of electric energy per unit charge produced inside a source of electrical energy

Front 10

Electron capture

Back 10

Process in which an inner-shell electron of an atom is captured by the nucleus

Front 11

Electron volt

Back 11

Amount of energy equal to 1.6x10^-19 J defined as the work done when an electon is moved through a pd of 1V

Front 12

Endoscope

Back 12

Optical fibre device used to see inside cavities

Front 13

Energy

Back 13

The capacity to do work

Front 14

Energy levels

Back 14

The energy of an electron in an electron shell of an atom

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Equilibrium

Back 15

State of an object when at rest or in uniform motion

Front 16

Error bar

Back 16

Representation of an uncertainty on a graph

Front 17

Error of measurement

Back 17

Difference between a measured value and the true value. Errors include systematic (including zero error) and random

Front 18

Excitation

Back 18

Process in which an atom absorbs energy without becoming ionised as a result of an electron inside an atom moving from an inner shell to an outer shell

Front 19

First harmonic

Back 19

Pattern of stationary waves on a string when it vibrates at its lowest possible frequency

Front 20

Fluorescence

Back 20

Glow of light from a substance exposed to ultraviolet radiation; the atoms de-excite in stages and emit visible photons in the process

Front 21

Force

Back 21

Any interaction that can change the velocity of an object

Front 22

Free body force diagram

Back 22

A diagram of an object showing only the forces acting on the object

Front 23

Frequency

Back 23

The number of cycles of a wave that pass a point per second

(# of oscillations per second)

Front 24

Friction

Back 24

Force opposing the motion of a surface that moves or tries to move across another surface

Front 25

Gamma radiation

Back 25

High-energy photons emitted by unstable nuclei or produced in particle annihilations

Front 26

Gravitational field strength

Back 26

Force of gravity per unit mass on a small object

Front 27

Ground state

Back 27

Lowest enegy state of an atom

Front 28

Hadron

Back 28

Particles and antiparticles that can interact through the strong interaction

Front 29

Hooke's law

Back 29

The extension of a spring is proportional to the force needed to extend it

Front 30

Inertia

Back 30

Resistance of an object to change of its motion

Front 31

Interference

Back 31

Formation of points of cancellation and reinforcement where two coherent waves pass through each other

Front 32

Internal resistance

Back 32

Resistance inside a source of electrical energy; the loss of pd per unit current in the source when current passes through it

Front 33

Ion

Back 33

A charged atom

Front 34

Ionisation

Back 34

Process of creating ions

Front 35

Isotopes

Back 35

Atoms of an element with different numbers of neutrons and the same number of protons

Front 36

Kaon (or K meson)

Back 36

A meson that consists of a strange quark or antiquark and another quark or antiquark

Front 37

Kinetic energy

Back 37

The energy of an object due to its motion