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1
Q

What does a substance that loses electrons become

A

Positively charged

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2
Q

What happens if charges in an ion:
Are the same.
Opposite.
One is charged the other isn’t.

A

Repel
Attract
Attract

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3
Q

How can you tell if an insulator is charged

Two

A

It attracts small pieces of dust and paper

When a balloon is charged it sticks to a wall

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4
Q

Two problems with static

A

Dust and dirt are attracted to insulators such as computer screens

Clothes made from synthetic materials cling to each other and to the body

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5
Q

Two dangers of static

A

If there are flammable gases or a high concentration of oxigen a spark could ignite the gases and cause an explosion

If you touch something with an electric charge on it it gives you a shock and could cause a heart attack

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6
Q

Safety measures from static shocks

A

An object that might be charged is connected to the earth by a wire so any charge disapaits

In a factory workers stand on an insulator matt so charges can’t be earthed through them

Lorries containing flammable liquids and gases are connected to the earth through earth through earth wire befor being loaded

When an aircraft is fueled static can build up this can causes sparks which can ignite the fuel a wire is used to earth the aircraft before it is fueled

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7
Q

What are five examples of uses of static

A

Photocopiers and laser printers

Defibrillators

Electrostatic dust precipitators

Paint spraying powder coats

Insecticide sprays

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8
Q

What is an electrical currant

A

A flow of electrical charge

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9
Q

How does a conventional current flow

A

From the post stove side of the terminal to the negative side

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10
Q

In what direction do electrons move compared to the conventional current

A

The opposite way

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11
Q

How do electrical conductress differ to insulators

A

Their electrons can move from atom to atom

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12
Q

What is the unit of charge

A

The coulomb c

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13
Q

What is the uk mains supply’s voltage and frequency

A

230v

50hz

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14
Q

What happens to the current when the components are connected in series

A

The current is the same

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15
Q

What happens to the current of components connected in parallel

A

It is shared

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16
Q

What is the word used to describe the fact that the total current going into the split in a parallel circuit is the same as the one going out

A

The current is CONSERVED

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17
Q

What is the unit for current

A

Amperes

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18
Q

How must an ammeter be connected into a circuit

A

In series

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19
Q

What does a substance that gains electrons become

A

Positively charged

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20
Q

How must a voltmeter be connected to a circuit

A

In parallel

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21
Q

If two 1.5v cells are connected in series in opposite direction what is the voltage

A

0

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22
Q

If two 1.5v batteries are connected in series facing the same direction what is the voltage

A

3v

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23
Q

What is the relationship between energy transferred, potential difference and charge

A

Joules=voltage x coulombs (charge)

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24
Q

What is the unit for resistance

A

Ohms

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25
What do resisters do in a circuit
Reduce the amount of current flowing
26
What is the name for a variable resistor
Rheostat
27
What happens to the current as you increase the potential difference
It increases
28
What is the equation for the relationship between resistance voltage and current
Resistance=voltage/current R= v/a
29
What is the relationship between voltage current and resistance
Voltage=current x resistance
30
What is ohms law
The result that the current flowing through a resistor=the voltage across the resistor. Providing the temp stay the same
31
What does it mean if the current flowing through a resistor is directly proportional to the voltage across it
It follows ohms law
32
Does a filament lamp follow ohms law
No, the resistance increases as the current increases
33
What is the current potential difference graph for a diode
A straight line then a steep line going to the right This is because diodes have a very high resistance one way so it can only flow the other way
34
What is a thermistor
Thermistors are temperature sensors their resistance decreases as the temperature increases A use is in fire alarms
35
What is the symbol for a thermistor
A rectangle in the circuit with a line underneath it which then turns and goes through the box at a 45 degree angle
36
What are ldr's
Light dependant resistors. Used in automatic security lights. Their resistance decreases as the light intensity increases
37
What is the symbol for an ldr (light dependant resistor)
A rectangle in the circuit with a circle around it. Stows point to it in accordance to where the light is coming from
38
What is the energy transfer I'm a resistor | Plus two uses
Some of the energy from the electrical current gets turned into heat Heating water in an electric kettle Electric fires
39
What causes the heat transfer in wires
The free flowing electrons colliding with ions in the lattice structure of the metal each collision causes heat to transfer to the lattice
40
What happens to a resistor as it's temperature increases.
It's resistance increases
41
What is diplacement
Distance traveled in a straight line
42
What is the velocity
The velocity of an object is its speed in one pert inculcate direction
43
What are the four vector quantities of a moving object
Displacement Velocity Acceleration Force
44
How do you find the distance traveled on velocity time graphs
The area below the line
45
What are the two factors in the size of acceleration
The size of the resultant force Doubling the resultant force doubles the acceleration The mass Doubling mass halves the acceleration
46
What is the strength of gravity on earth
Ten newtons per kilogram
47
The three stages of falling
Acceleration downwards of the object no air resistance Resultant force is acting downwards Object gains speed weight stays the same but air resistance increases Resultant force is acting downwards Weight is balanced with air resistance there is no resultant force reaches terminal velocity
48
How do seat belts prevent injury in a car crash
Stop you moving inside the car Stretch slightly to reduce the time taken for the body to reach zero so reduces forces on it
49
How do airbags help you survive a car crash
Increase the time for the heads movement to reach zero to reduce forces on it Act as a cushion to stop cuts
50
What two things the amount of work done depend on
The size of the force on the object The distance the the object moves
51
What is the relationship between work done by brakes and the loss in kinetic energy
Work by brakes=loss in kinetic energy
52
What happens to the braking distance of a car if it's speed doubles
It quadruples
53
What does power measure
How quickly work is being done
54
What is the measure of power
Watts
55
What does the amount of gravitational potential energy depend on
Mass Height above ground
56
What are the gravitational field strengths of the earth moon and Jupiter
Earth 10n Moon1.6n Jupiter26n
57
What are the dependant values on the size of kinetic energy in a moving object
Speed and mass
58
What is the relationship between work done by brakes and the loss in kinetic energy
They are equal
59
What is an example of conservation of energy
Newtons pendulum
60
What makes a material radioactive
The nucleus of the atom is unstable and can decay by giving off radiation in the form of alpha particles beta particles or gamma rays
61
What is used to measure radioactivity
A Geiger counter
62
What is the activity of a radioactive material measured in
Becquerels
63
What is the activity of a radioactive material
The number of nuclei that decay and give off radiation every second
64
What is an alpha particle made of
Two protons and two neutrons, same as a helium nucleus
65
What is a beta particle made of
A fast moving electron
66
What is a gamma ray made of
High energy electromagnetic radiation
67
How well does gamma ionise
Weakly
68
How well do alpha particles ionise
Very well
69
How well do beta particles ionise
Medium
70
What happens after alpha decay
A new element is formed two places lower in the periodic table
71
What happens after beta decay
The nucleus has one more proton and one less neutron
72
Steps of fission 4
Neutron fired into nucleus Neutron hits nucleus Nucleus splits into smaller nuclei called daughter nuclei and releases two or three more neutrons The released neutrons hit more uranium nuclei
73
Where is the most dangerous nuclear waste stored
Glass like blocks deep in the ground
74
How else can a nuclear reactor be used
Can make other nuclei radioactive because they absorb the neutrons which makes their nuclei unstable These are used as tracers in hospitals
75
How do control rods reduce reaction speeds and what are they made of
When hit by a neutron the daughter nuclei make two or three extra neutrons, this reaction is a chain reaction and if not controlled would easily spiral out of control Control rods are made of boron which absorbs the neutrons, this slows down the reaction as less neutrons are hitting new nuclei The control rods are lowered to slow the reactiOn down and raised to speed it up
76
Two steps of fusion
Two hydrogen atom collide and fuse together The hydrogens fuse to produce a helium atom and energy
77
What is the difficulty of nuclear fusion
Both hydrogen atoms are positively charged which causes electrostatic repulsion so it has to be very hot for the nuclei to coliseum as they then move faster Pressure and heat have to be very high and are more expensive to produce than the energy made by fusion
78
Why was cold fusion never considered to work
Many attempts to reproduce the results failed So it did not pass the peer review
79
How do rocks emit radiation
Radon gas emited
80
How is alpha radiation used
Smoke detectors Americium releases alpha which ironises the air in a detector smoke from fire ionises differently and causes the alarm to go off
81
What are the uses of beta two
Medical tracers certain chemicals concentrate in damaged or diseased parts of the the body radiation detectors are placed around the body to build an image of the inside Measuring thickness of materials The thicker the material the more radiation is absorbed and the less radiation reaches the detector The detector then sends signals to the machine to decrease the size of the material
82
Uses of gama
Treatment of cancer Sterilising medical equipment no heat so plastics can be sterilised
83
What does the rate of nuclear decay depend on
The type of material The number of un decayed nuclei present the greater the rate
84
How is carbon fourteen formed
Cosmic rays hitting he atmosphere
85
How is carbon dating done
Using the half life of carbon 14 we can judge the age of something as the amount of carbon 14 on earth always stays the same
86
How is the age of rocks found
The ratio of uranium to lead As the rock gets older there is more lead available
87
What accounts for the most background radiation
Radon gas
88
Dangers of ironising radiation on the body
Breaks molecules into fragments The ions then react with other molecules in cells Charged particles can react with DNA which causes mutations and cancer
89
Five precautions around radioactivity
Using tongues to pick up sources Surveys kept in lead containers Sources never pointed at people Protective clothing Exposure times limited
90
Disadv to nuclear energy
Non renewable If accident large amounts of radiation released Nuclear waste stays radioactive for thousands of years
91
How is low level waste disposed
Put in drums and submerged in concrete
92
How is intermediate level waste disposed
Mixed with concrete then put in stainless steel drum
93
How is high level n waste stored
Stored under water in large pools for 20 years then put in underground store where air can circulate and cool it

Chem (9 decks)

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