Modern Physics Flashcards

(30 cards)

1
Q

Electron

A

A subatomic particle which orbits the nucleus full stop has a charge of e which is the fundamental quantity of charge

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2
Q

Thermonic emissiom

A

The release of electrons from the surface of a hot metal

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3
Q

Work function

A

The minimum energy required by a photon to remove the losses electron from the surface of a metal

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4
Q

X Rays

A

Electromagnetic radiation of extremely high frequency, short wavelength which are produced when high speed electrons strike a heavy metal target

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5
Q

Photoelectric effect

A

The release of electrons from the surface of a metal due to electromagnetic radiation of a suitable frequency hitting is

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6
Q

Photon

A

A discrete packet of electromagnetic energy. Its energy depends on its frequency
E = hf

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7
Q

Threshold frequency

A

The minimum frequency needed for photoelectric emission

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8
Q

Protons

A

Positively charged nucleons with the same size charge as the electron

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9
Q

Neutrons

A

Electrically neutral nucleons, they have slightly more mass than protons

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10
Q

Atomic Number

A

The number of protons in the nucleus of an atom

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11
Q

Mass number

A

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

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12
Q

Isotopes

A

Ashams which have the same atomic number but different atomic mass

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13
Q

Radioactivity

A

The spontaneous emission of radiation due to the natural disintegration of an unstable nucleus

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14
Q

Ionisation

A

The charging of a neutral atom or molecule when it loses or gains water more electrons

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15
Q

Penetration

A

The distance the radiation travels through a medium

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16
Q

Radioisotope

A

An unstable isotope of an element that the case spontaneously, emitting radiation

17
Q

Alpha radiation

A

The emission of a helium nucleus from a large atom

18
Q

Beta radiation

A

The emission of an electron when a neutron decays into a proton

19
Q

Gamma radiation

A

The emission of high energy photons from an unstable nucleus

20
Q

Activity

A

The number of nuclei in a radioactive sample decaying per second

21
Q

1 Becquerel

A

Units of activity equaling 1 disintegration per second

22
Q

Law of radioactive decay

A

The activity of a sample is directly proportional to the amount of present
A=-λN

23
Q

Half life

A

The time taken for half of the atoms present in a radioactive sample to decay
T= ln2/λ

24
Q

Nuclear fission

A

The splitting of a large nucleus into two smaller nuclei, of roughly equal mass, with emission of neutrons and release of energy

25
Nuclear fusion
The joining up of two smarter nuclei to form a larger nucleus with release of energy
26
Chain reactions
Reactions were at least one neutron is released during each fission reaction
27
1 electronvolt
The energy gained or Lost by an electron when it moves through potential difference of 1 V
28
Critical mass
The minimum amount of the fissile material needed in order for chain reactions to occur
29
Radiation
The emission of particles of matter or photons of energy
30
Background radiation
Radiation that comes from environmental sources including the Earth's crust, the atmosphere, cosmic rays and radioisotopes