P7(Radioactivity) Flashcards

1
Q

What were the 3 observations from Rutherfords experiment

A

-Most alpha particles went straight through
-Some alpha particles were deflected at an angle
- very few 1 in 10,000 were deflected at an angle more than 90 degrees

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2
Q

What were the 3 conclusions from Rutherfords experiment

A

-Most of the space in an atom is empty
-there is some volume in an atom that is positively charged
-this positive volume is very small

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3
Q

What is the structure of an alpha particle

A

2 protons and 2 neutrons

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4
Q

What is the structure of a beta particle

A

High energy electron

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5
Q

What is the structure of gamma radiation

A

Electromagnetic wave

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6
Q

What is the charge of an alpha particle

A

Positively charged

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7
Q

What is the charge of a beta particle

A

Negatively charged

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8
Q

What is the charge of gamma radiation

A

Neutral

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9
Q

What is the deflection for an alpha particle

A

Will be deflected by electric fields by positive side

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10
Q

What is the deflection for a beta particle

A

Will be deflected by electric field by negative side

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11
Q

What is the deflection for gamma radiation

A

Won’t be deflected by electrical field

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12
Q

What is the ionising power for an alpha particle

A

Highly ionising

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13
Q

What is the ionising power for a beta particle

A

Less ionising than alpha

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14
Q

What is the ionising power for Gamma

A

Least ionising

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15
Q

What is the penetration power for alpha

A

Least penetrating only travels few cm in air
-can be stopped by paper

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16
Q

What is the penetration power for beta

A

More penetrating than Alpha travels few metres in air
-can be stopped by thin aluminium

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17
Q

What is the penetration power for Gamma

A

Infinite distance
-stopped by thick lead and concrete

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18
Q

What are the uses for alpha radiation

A

Used in smoke alarms

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19
Q

What are the uses for beta radiation

A

Used to monitor thickness of paper or thin aluminium sheets

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20
Q

What is the uses of Gamma radiation

A

Used to treat cancer and it’s used to sterilise hospital equipment

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21
Q

What are the differences from the plum pudding model and nuclear model

A

-the plum pudding model has negative electrons evenly spaced out
-the plum pudding model has a positively charged sphere
-the nuclear model has negative electrons in random orbits, orbiting the nucleus
-the nuclear model has a nucleus formed of protons and neutrons which makes the nucleus have a neutral charge

22
Q

How does a smoke alarm work

A

-Alpha particles ionise air molecules between the charged plates
-Circuit is completed live current through the gap
-smoke particles do not get ionised
-breaks circuit and alarm sound goes off

23
Q

How is the thickness of the of paper monitored by beta radiation

A

-For constant thickness count rate does not change
-Increased thickness count rate decreases
-decreased thickness count rate increases
-detector sends message to computer to reset the thickness
-Alpha not suitable because u will not pass through paper
-Gamma not suitable as it will pass through paper unaffected

24
Q

What is an alpha particle

A
25
Q

What happens when an atom loses an alpha particle

A

The atomic mass number
decreases by 4
-The proton number
decreases by 2

26
Q

What is a beta particle

A
27
Q

What happens to an atom when beta(-) decay occurs

A

The atomic mass number remains
the same
-The proton number
increases by 1

28
Q

What is radioactivity

A

The process in which radioactive elements decay by giving out alpha,beta or gamma radiation

29
Q

What is count rate(Activity)

A

Number of atoms decaying per unit time

30
Q

What is the formula for count rate(Activity)

A
31
Q

Which radioactive isotope will be most suitable for medical treatment

A

half life of tracer must be such that it lasts till the tests have been completed
-decay almost completely after the tests
-decay into a stable product
-least ionising so it doesn’t damage living cells
-highly penetrating enough to reach detectors
-Gamma is most suitable

32
Q

What is nuclear fission

A

Process in which a larger unstable nucleus splits into 2 smaller and stable nucleus, 2 or 3 neutrons and a large amount of energy

33
Q

Diagram of nuclear fission

A
34
Q

What are the components of a nuclear reactor

A

Fuel rods- made up of fissionable material
Control rods-made up of boron absorbs neutrons to slow down the process or shut it down
Moderator-made up of heavy water
Shielding- Around the nuclear reactor made from concrete and lead, prevent leak of nuclear radiation

35
Q

What is nuclear fusion

A

Process in which 2 smaller nuclei fuse together to form larger nucleus and large amount of energy

36
Q

How does nuclear fusion work

A

-When 2 protons fuse together they form a Heavy hydrogen nucleus
-two more protons collide with the heavy hydrogen nucleus turning the nuclei into heavier nuclei
-the 2 heavier nuclei collide to form the helium nucleus

37
Q

What are the advantages of nuclear fusion

A

-large amounts of energy produced
-no harmful gases produced
-hydrogen is a raw material is abundant
-no nuclear waste produced
-byproduct is helium gas which is unreactive

38
Q

What is disadvantages of nuclear fusion

A

-Technology is still in early stages of development
-energy to extract hydrogen may be taken from fossil fuels
-large amounts of energy is needed to initially start nuclear fusion

39
Q

Comparing fission with fusion

A

Fission:
-larger nucleus splits into 2 smaller stable nuclei
-2 or 3 neutrons are produced
-energy released in form of gamma radiation
-a slow moving neutron hits unstable nucleus
-nuclear waste is produced
-technology is well known
Fusion:
-2 smaller nuclei fuse to form larger nucleus
-no neutron produced
-energy released in form of gamma radiation
-large amounts of initial energy is needed
-no nuclear waste produced
-technology is in early stages

40
Q

How does nuclear fission work

A

a slow moving neutron hits a large unstable nucleus
-larger nucleus splits into 2 smaller stable nuclei
-2 or 3 neutrons are produced
-chain reaction is created as the neutrons emitted hit other unstable nuclei
-energy released in form of gamma radiation

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50
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