Nuclear Flashcards

1
Q

charge on proton/electron (not exact coulombs)

A

1e

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2
Q

alpha decay equation and process

A

helium nucleus (2p, 2n)
mass number down by 4, atomic number down by 2

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3
Q

beta decay equation and process

A
  • a electron or positron given off
  • neutron turns into proton or vice versa
  • mass number same, atomic number one up or one down
  • anti neutrino for -, neutrino for +
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4
Q

Ionisation
Penetration
Stopped By

A

Alpha, Beta, Gamma

Ionisation: high, mid, low
Penetration: low, mid, high
Stopped By: paper, aluminium, lead

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5
Q

uses of three radiations

A

alpha: smoke detector
beta: paper thickness gauge
gamma: sterilising, radiotherapy

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6
Q

What is gamma radiation

A

nucleus does not change
gets rid of spare energy

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7
Q

Decay constant in radioactivity

A

λ
probability of a nucleus decaying in the next second

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8
Q

Bq

A

number of decays per second

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9
Q

Half life meaning

A

time taken for radioactive activity to half

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10
Q

Activity, decay constant, number of undecayed nuclei left

A

A = λN

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11
Q

ratio of activity, mass, number against time and decay constant

A

A/A0 = M/M0 = N/N0 = e^-λt

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12
Q

half life equation

A

t = ln(2)/λ

where t is half life

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13
Q

time constant meaning (2)

A

time when we have 37% of original value
(1/e)

when λt = 1

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14
Q

time constant, decay constant

A

tc = 1/λ

where tc is time constant

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15
Q

measured activity / true activity

when a small detector is measuring count from a central gamma source

A

measured activity / true activity

Area of detector/4πr^2

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16
Q

intensity from radiation source

A

intensity = radiation/area

I = k/4πr^2

17
Q

intensity, distance realstionship

A

I ∝ 1/r^2

I1r1^2 = I2r2^2

  • if detector moved x3 far away, intensity down by 1/9
18
Q

parts of a fission reactor and purposes

A
  • coolant - remove heat from core
  • fuel rods
  • moderator - slows down neutrons to increase fission (eg. water)
  • control rods - absorbs some neutrons to reduce chain reaction (eg. boron)
19
Q

what they do with radioactive waste

A

vitrify and bury

20
Q

where Fusion happens

A

sun
H- bombs

21
Q

unit of relative atomic mass

22
Q

mass of constituents vs mass of nucleus

A

mass of constituents > mass of nucleus

23
Q

mass defect

A

change in mass from nucleus constituents to nucleus
converted to energy

24
Q

binding energy

A

energy required to separate a nucleus/atom into its constituents

25
energy, mass
E = Δmc^2 where mass is in kg
26
1u to kg
1u = 1.67 x 10^-27 kg
27
u to MeV
x 931.3
28
1 MeV to joules
1 MeV = 1.6 x 10^-13 J
29
binding energy change in fission and fusion
- total binding energy increased - mass lost
30
what makes nucleus stable (binding energy)
binding energy per nucleon increases
31
cone of stability and where types of radiation happen
- stability cone above N = Z - B- above - B+ below - alpha top corner
32
Rutherford scattering setup
- alpha transmitter - gold foil - detector that can co all the way round
33
Rutherford scattering results and conclusions
Results - most alpha particles passed straight through foil - few deflected by >4 - very few deflected by >90 Conclusions - atom is mostly empty space - concentration of positive charge in atom - nucleus has high density and mass
34
electrical potential energy equation
Ep = Qq/4πε0r where Q and q are the two charges r is distance of separation
35
find closest approach to approximate radius of nucleus
initially Ek = 1/2 mv^2 at point of repulsion, all Ek into Ep Ep = (2e)(Ze)/4πε0r 1/2 mv^2 = (2Ze^2)/4πε0r r = (Ze^2)/πε0mv^2