Paper 2 content Flashcards

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1
Q
A
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2
Q

Why is temperature constant when changing state

A

energy is used to overcome potential energy

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3
Q

Define thermal eqm

A

heat flow stops when it reaches the same temp.

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4
Q

what does ΔU +ve mean

A

the system gains internal energy

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5
Q

what does +ΔQ mean

A

system gains heat energy

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6
Q

what does ΔWD mean

A

work done by the system

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7
Q

define specific heat capacity

A

energy to raise 1kg of mass by 1 deg. without change of state

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8
Q

define specific latent heat

A

energy needed to change 1 kg of mass from one state to another without raising its temperature

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9
Q

what state to what state is fusion

A

solid to liquid

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10
Q

what state to what state is vapourisation

A

liquid to gas

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11
Q

similarity of gravitational and electric field [2]

A
  1. follow inverse sq. law
  2. use field lines to represents
  3. have equalpotential lines
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12
Q

differences between gravatational and electric fields [2]

A
  1. g-fields always attract
  2. electric field repels/attract depends on charge
  3. acts on different body (masses/charges)
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13
Q

define fields

A

a region at which a body experiences a non-contact force

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14
Q

What is the gravatational potential at infinity

A

0

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15
Q

main idea of Kepler’s 3rd law

A

T^2 = r^3

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16
Q

how to calculate potential difference

A

ΔV = Vf -Vi

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17
Q

gradient of potential and seperation

A

field strength

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18
Q

area under field strength and seperation graph

A

change in potential

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19
Q

define geosynchronous orbit

A

orbits in the same period as the planet’s

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20
Q

define geostationary

A

special e.g. of geosynchronous

stay above the same spot of the planet

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21
Q

name one use of low orbit

A

weather

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22
Q

direction of electric field lines

A

+ve to -ve

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23
Q

define absolute electric potential

A

WD per unit charge to bring it from infinity to point

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24
Q

What happens potential when moving closer to +ve charge

A

increases - as WD needed for +ve test charge to get closer

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25
Q

what happens to potential when moving away from +ve Q

A

decreases - no WD by test charge as there’s repulsion

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26
Q

what happens to potential when moving towards -ve Q

A

decreases - WD by field - as attracted

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27
Q

what is the effect of opposing electric field on capacitance

A
  1. greater electric field strength
  2. increases permitivity
  3. greater capacitance
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28
Q

RC and half life conversion

A

t1/2 = 0.69RC

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29
Q

define magnetic flux density

A

Force per metre of wire carrying 1A perpendicular to the field

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30
Q

Define Faraday’s law

A

emf is proportional to rate of change of magnetic flux

31
Q

Define Lenz’s law

A

Direction of induced emf opposes the motion causing it (change of magnetic flux that causes it0

32
Q

Unit for magnetic flux

A

Wb

33
Q

Define magnetic flux

A

Amount of magnetic field passing through an area

34
Q

What is magnetic flux linkage

A

the amount of magnetic field passing through a coil of wire

35
Q

what is eddy current ?

A

heat loss caused by the opposing current produced

36
Q

solution to eddy current

A

laminated core
- eddy current can’t pass through between layers
-amplitude of overall current is lower

37
Q

3 sources of energy loss by transformers

A
  1. eddy current
  2. magnetizing and demagnetizing core
  3. resistance in coil
38
Q

solution to energy loss to mag and demag core

A

use softer core - easier to mag and demag

39
Q

solution to resistance in coil

A

use thicker wires

40
Q

Why is ionising radiation dangerous?

A
  1. DNA alteration
  2. cell damage, mutation => cancer
  3. change func. of enzymes
41
Q

Define radiation dose

A

energy absorbed per body mass

42
Q

Define dose equivilent

A

the measure of damage done by radiation

Dose eq. = rad. weighing factor * dose

43
Q

Application of alpha radiation

A

Smoke alarm

  1. allow current to flow
  2. won’t travel far
  3. when smoke present, alpha particles are intercepted
  4. triggering alarm
44
Q

application of beta radiation

A

thickness detector

(thicker = less beta passes)

45
Q

app. of gamma radiation

A

Radiotracers
- diagnose without need of surgery
- short half life + less ionising

Cancer treatments
- radiation damages cells
-high dosage targeted at centre of tumour
- shielding needed to protect staff

46
Q

App. of Carbon-14

A

radioactive dating

  • plants take in CO2 as part of photosynthesis
  • plants stores the C-14 when they die
  • could be used to date the plant
47
Q

define binding energy

A

energy needed to split nucleus to its constituents nucleons

48
Q

what is binding energy equivilent to ?

A

total mass defect

E(individual nucleon) > E( in nucleus)

49
Q

Observation from binding energy - mass no. graph [2]

A
  1. three peaks - O, N, He most stable - multiple of alpha
  2. highest point - Fe (most stable nucleus)
  3. avg. binding energy increases rapidly initially
  4. decreases gradually as n. increases
50
Q

E.g. material for fuel rod

A

Uranium -235

51
Q

E.g. for moderator

A
  1. heavy water
  2. graphite
52
Q

material for control rod

A
  1. boron
  2. cadmium
53
Q

material for coolant

A
  1. water under pressure
  2. carbon dioxide
54
Q

function of moderator

A

slows down fast neutrons - further fission

55
Q

what is produced in a fission reaction

A

2 daughter nuclei + 2 or more neutrons

56
Q

func. of control rods

A

slows down reaction by absorbing neutrons

57
Q

2 main observation of rutherford scattering

A
  1. most alpha particles passes straight through
  2. some deflected at large angle
58
Q

conclusion from rutherford scattering

A
  1. atoms have a very small centre
  2. nucleus contains almost all the mass
59
Q

3 sources of background radiation

A
  1. radon gas
  2. cosmic ray
  3. naturally occuring iostopes
60
Q

what processes occurs when too many protons

A

beta-plus decay
electron capture

61
Q

what process occers when too many neutrons

A

beta-minus decay

62
Q

Why is technetium-99m used for medical diagnose

A
  1. metastable - half life greater than 10^-9
  2. emits gamma
63
Q

2 methods to determine the radius

A
  1. estimation by closest approach
  2. determination by electron diffraction
64
Q

When does fission occurs

A

E(starting nucleus)> E(daughter)

65
Q

When does fusion occurs

A

E(starting nuclei)<E(fused)

66
Q

fission

what happens when mass < critical mass

A

fission eventually slows down

67
Q

nuclear reactor

How to handle waste

A
  1. encased in cement
  2. store underground
  3. vitrification
  4. cooling in storage
  5. further encased with lead containers
68
Q

nuclear reactors

3 precaution

A
  1. shielding
  2. reduce exposure
  3. remotely handle with tongs
  4. emergency shut-down protocol
69
Q

3 pros of nuclear reactor

A
  1. no production of greenhouse gas
  2. highly reliable
  3. not weather dependent
70
Q

nuclear reactors

3 cons

A
  1. dangerous
  2. expensive to handle waste
  3. have potential to cause catastophic consequence on envrionment and surrounding communities
71
Q

Define mass defect

A

mass lost that is converted into energy

72
Q

What is needed to be acc. when using GM-counter

A
  1. background
  2. corrected distance
73
Q

Assumptions for kinetic theory model

A
  1. Volume of molecules are negligible
  2. Collision are elastic
  3. Collision time is negligible compared to time between collision
  4. No intermolecular forces between molecules
74
Q

Why does a molecule exert a force on the wall of cylinder

A
  1. Direction changes for molecule
  2. Therefore change in momentum
  3. Resultant force acting on molecule
  4. Equal and opposite force acting on cylinder wall