Paper 2 Overview Flashcards

Question

SP10b - How does potential difference differ in parallel and series circuits?

Answer 1

* S: The p.d is different across different components, directly proportionate to the resistance of that component * P: The p.d is tha same at all points across the circuit

Answer 2

* The flow of electrons * The rate of flow of charge

Answer 3

C - Coulombs

Answer 4

Q = I x t | (Charge = Current x time)

Answer 5

**E = Q x V** (Energy = Charge x p.d) since **Q = I x t**, this means that **E = I x t x V** (Energy = Current x time x p.d)

Answer 6

V = I x R (p.d (V) = Current (A) x Resistance (Ω))

Answer 7

The force pushing back against p.d opposing and reducing the current.

Answer 8

* Series: Add up the resistance of all the components * Parallel: 1/R_T = 1/R₁ + 1/R₂+ ...........

Answer 9

* S: It is greater than any of the individual resistances * P: It is smaller than all of the individual resistances

Answer 10

* It is a straight diagonal line showing direct proportion. * This is because resistors are ohmic conductors. * The voltage is directly proportionate to the current.

Answer 11

A component in a circuit that follows Ohm's rule of V=IxR

Answer 12

The inverse of the resistance (1/R)

Answer 13

* A line that is nearly on the x-axis till it shoots up. * This is because a diode has an infinitely high resistance till a point where it has an infinitely low resistance

Answer 14

* An S shaped 'curve'. * This is because the resistance of a lamp increases due to the temperature increase as it conducts electricity at a higher voltage

Answer 15

* The x-axis would be temperature (°C) and the y-axis would be resistance (Ω) * As the temperature increases, the resistance decreases. This forms a negative curve in an L shape * This can be used to reduce the current in lower temperatures.

Answer 16

* The x-axis would be light intensity (lux) and the y-axis would be resistance (Ω) * As the light intensity increases, the resistance decreases. This forms a negative curve in an L shape * This is used for lit up signs outside. In darker conditions (lower light intensity) bulbs don't need to be as bright. * Thus, the resistance is higher to reduce the current and brightness * Resistance is high against the dark side #Starwars

Answer 17

* Set up a series circuit with a power pack, an ammeter, a fixed resistor and a voltmeter in parallel to this. * Provide different voltages from the power pack. * For each voltage provided, note down the current - Replace the fixed resistor with a lamp and repeat * Set up the circuit from here so that there is a voltmeter attached in parallel to this. * Attach another lamp to the circuit with another voltmeter in parallel to this * Measure out the voltages and currents when different voltages are supplied * Move one of the bulbs with its voltmeter to a new branch forming a parallel circuit * Add an ammeter to each branch of the circuit * Now measure the voltage and current depending on the voltage provided

Answer 18

* The heating effect is when a circuit warms up due to the resistance in its wires. * Work is done against the resistance and so energy is transferred. * This is in the form of heating and dissipates into the surroundings

Answer 19

* In appliances such as electric heaters and kettles where the aim is to use thermal energy, the heating effect is incredibly useful. * In these circuits, resistance tends to be high.

Answer 20

* Current is the flow of electrons. * A metal is made of electrons flowing around positive metal ions * When the electrons are moving in the circuit, they can collide into these posistive metal ions. * These collisions are resistance and they transfer energy

Answer 21

* Choosing a metal with a lower resistance * Using a thicker wire (more space for electrons to flow) * Using a shorter wire (less distance in which they can collide)

Answer 22

E = I x t x V Energy = Current x time x Voltage

Answer 23

* P = E/t * P = I x V * P = I² x R * P = V² ÷ R

Answer 24

* We know that P = I x V and that V = I x R * If we substitue the V in the first equation we get P = I x I x R or P = I² x R * If we rearrange V = I x R we get I = V ÷ R * So if we substitute this in we get P = V x V ÷ I or P = V² ÷ R

Answer 25

* 230V * 50Hz (changes diretion 50 times per second) * a.c

Answer 26

**d.c**: * Only one direction (positive to negative) * Electrons loose energy as they travel from negative to positive * A graph showing the direction will only ever be on one side of the x-axis **a.c**: * Constantly switching direction (this is their frequency) * Electrons vibrate and pass on energy * A graph showing direction will contantly cross zero and over the x-axis _{A̶C̶/̶D̶C̶ ̶a̶r̶e̶ ̶a̶n̶ ̶A̶u̶s̶t̶r̶a̶l̶i̶a̶n̶ ̶r̶o̶c̶k̶ ̶b̶a̶n̶d̶ ̶f̶o̶r̶m̶e̶d̶ ̶i̶n̶ ̶S̶y̶d̶n̶e̶y̶ ̶i̶n̶ ̶1̶9̶7̶3̶ ̶b̶y̶ ̶b̶r̶o̶t̶h̶e̶r̶s̶ ̶M̶a̶l̶c̶o̶l̶m̶ ̶a̶n̶d̶ ̶A̶n̶g̶u̶s̶ ̶Y̶o̶u̶n̶g̶.̶}

Answer 27

* Live wire: Connects the appliance to the generators at the power station providing 230V * Neutral wire: The return path to the power station and will be at 0V if circuit is correctly connected * Earth wire: Connects the metal parts of the appliance to a large spike of metal that pushes down and connects to the ground. Will be at 0V unless the circuit is incorrectly connected * Fuse: A Safety device usually 3, 5 or 13 A * Plastic casing: This electrical insulator allows you to safely hold the plug

Answer 28

* If a wire comes loose and touches the metal part of the appliance, the electricity will beable to flow through this. * When a person touches it, the electricity can pass through the person to the ground. * This would give them an electric shock. * However the earth wire provides an easier way to travel to the ground. * As electrcity always takes the past of least resistance, it goes this way and the person doesn't get an electric shock

Answer 29

* A fuse is a glass tubing with a thin metal wiring that the electricity passes through. * A faulty appliance may draw too much current which would heat up and cause a fire. * However depending on the value of the fuse, it will melt once the current has reached a certain level and cause the circuit to be incomplete meaning current stops flowing through it

Answer 30

* Fuses are typically found in 3A, 5A, and 13A. * You want to pick one that has a current higher than what the current of the appliance is but not to high. * This way it will stop a fualty appliance but not a properly functioning one. * If an appliance has a current of 3A, you would pick a 5A fuse. 3A would be too low and 13A would be too high

Answer 31

* Circuit breakers are automatic swtiches that detect a rise in current and automatically switch off the supply safely. * They are an alternate to fuses.

Answer 32

* They can just be turned back on rather than having to buy a new fuse * They work quicker. * You elliminate the risk of an accident occuring while the fuse is melting

Answer 33

* Earth wire: Green and yellow * Neutral wire: Blue * Live wire: Brown

Answer 34

* Fuses are cheaper * More practical for small scale uses (e.g. small appliances)

Answer 35

* Both objects start off as neutral. * Electrons move from the acetate rod to the cloth so the acetate rod ends up positive and the cloth ends up negative.

Answer 36

* Both objects start off as neutral. * Electrons move to the polythene rod from the cloth so the polythene rod ends up negative and the cloth ends up positive.

Answer 37

* Repel * Attract * Repel

Answer 38

* If you rub a balloon against a jumper, the friction causes electrons to transfer from the jumper to the balloon. * The balloon now has a negative charge * When brought close to a wall, the negative charge of the balloon repels the electrons in the wall * The protons are brought closer to the surface of the wall as they are attracted to the balloons negative charge * The balloon is attracted to the positive charge on the surface of the wall causing it to stick * The wall has an induced charge

Answer 39

Friction between your feet and the floor and slight friction between you and the air builds up charges.

Answer 40

* By touching something made of conducting material, the electrons will jump to the object and head to the ground. * You may experience a small electric shock

Answer 41

* Static electricity builds up in clouds due to friction between ice and water particles in air currents. * The negatively charged particle move towards the bottom of the cloud. * As the ground is neutral, it is relatively positive to the cloud and so when the charge in the clouds is too great, they jump to the ground to discharge. * This produces a spark which is lightning.

Answer 42

* A tall building may install a lightning conductor. * This would be a metal structure that would be the tallest structure in an area that runs through the centre of the building to the ground. * This means that a cloud will discharge through this which wont affect the surrounding areas.

Answer 43

* As high amounts of fuel pass through the nozzle at a fast rate, this build up friction which charges the fuel droplets. * Once they have built up a great charge they want to discharge. * This would create a spark which would light the fuel causing an explosion. * The bonding line is attached which earths the aircraft so that the charge flows through easily to the ground without any spark.

Answer 44

The pipes and the car's tyres earth the car already.

Answer 45

* Electrostatic sprays: * Spray paint * Pesticide * Printers * Electrostatic precipitators

Answer 46

The nozzle contains electrodes which negatively charge the spray droplets. This leads to two things: 1. The like charge between all droplets spread them out 2. The negative charge attracts to the relatively positive object/crop and then charges it by induction to stick

Answer 47

* Since they spread out there is wide coverage * Since they attach through static induction there is even coverage * Since all the droplets attach, less spray is wasted

Answer 48

* A force field is the area around an object in which an object will experience a force and so... * An electrostatic field is the area around an object where a charged object will experience a force

Answer 49

* Both are a dot with equally spaced lines originating form the centre. * In a positive one there are arrows away and in a negative one they are towards

Answer 50

There will be more lines as they will be closer together

Answer 51

Where the lines are closest together

Answer 52

* Lines never cross * The closer the lines are is where the field is strongest * Start on the positive charge and end on the negative charge * Shows the direction of force on an object

Answer 53

A uniform parallel electrostatic field

Answer 54

Towards the negatively charged plate.

Answer 55

* A magnet has a magnetic field around it. * Once it moves throughout the wire, the field induces a P.d. in the wire which creates a magnetic field opposite to original change.

Answer 56

* A coil of wire wrapped around an iron core is rotated inside a magnetic field * Wires from the coil are connected to slip rings on the axle of the coil * The slip rings make electrical contact through carbon brushes * This produces an alternating current

Answer 57

Same concept as an alternator except: * The wires are connected to a split ring commutator * The commutator is connected to the carbon brushes * Every half-turn the connections are swapped * Thus, this produces a direct current

Answer 58

* (The opposite to loudspeakers) * Sound waves cause vibrations in air pressure * The pressure causes a diaphragm to move back and forth * The diaphragm moves a coil of wire back and forth * This causes the coil which is wrapped around a permanent magnet to gain an induced voltage and current * The amplitude of the wave affects the volume * The frequency affects the pitch * Converting sound energy into electrical energy

Answer 59

* (The opposite to microphones) * An a.c. voltage passes througha coil * This moves the coil along a permanent magnet * The coil hits the diaphram causing it to vibrate * This creates soundwaves * The higher the current, the larger the frequency and amplitude * And so the volume and pitch is higher * Converting electrical energy into sound energy

Answer 60

The system that connects power stations to homes to provide electricity nationally

Answer 61

Transformers are (not robots in disguise) devices that alter the voltage and current of electricity. * SU increase voltage; decrease current * SD decrease voltage; increase current

Answer 62

* Electricity is generated at the power station (11kV) * Stepped up (400kV) for transmission lines * Stepped down (33kV) Where some is used in large factories * Some is stepped down further (11kV) for small factories * Rest is stepped down instead (230V) to be used in houses shops etc.

Answer 63

* A higher voltage means a lower current. * A higher current would mean a higher power loss (P = I²xR). * So the lowest possible current is attained so that the least amount of energy is lost by heating. * Low resistance wires are also used (thicker).

Answer 64

A primary coil (connected to an a.c supply) and a secondary coil with differing amounts of turns, wrapped around an iron core.

Answer 65

* Changing a.c current supplied * This produces a changing magnetic field in primary coil * The iron core is induced and carries this changing magnetic field * This creates a changing magnetic field in the secondary coil * This induces a changing a.c voltage in the wires connected to the secondary coil.

Answer 66

V(p) x I(p) = V(s) x I(s) [assuming that the transformer is 100% efficient]

Answer 67

V(p)/V(s) = T(p)/T(s) V = Voltage across coil T = Turns in coil

Answer 68

* P = I x V * E = P x t , so * E = I x t x V

Answer 69

Everything is made of tiny particles

Answer 70

* Rigid * Fixed shape * Fixed volume * Cannot be compressed

Answer 71

* Not Rigid * No fixed shape * Fixed volume * Cannot be compressed(ish)

Answer 72

* Not Rigid * No fixed shape * No fixed volume * Can be compressed

Answer 73

* The particles change their arrangement * This leads to a change in density * The mass is conserved as the amount of particles remains * This is a physical change as it can be reversed and no new substances are formed

Answer 74

* Generally, as substances go from solid → liquid → gas, they become less dense * This is because the particles become more spread out meaning there are less in a certain volume * Water is the exception to this as ice is less dense than liquid water

Answer 75

Density is a measure of how many particles are packed in a space Density(g/cm³) = mass(g) ÷ volume(cm³) (ρ = m x V)

Answer 76

* Set an electronic balance to 0 then place the object on it and record the mass * Set up a displacement can leading into an empty measuring cylinder and fill the can with water * Place the object in the can. If it floats, then push it down till it is just under the surface of the water * Read the value for the volume of water in the measuring cylinder (from the bottom of the meniscus) * This is the volume of the object. Do mass/volume to find the density

Answer 77

The energy stored in the movement of particles that has been transferred to the system by heating

Answer 78

A measure of the average speed/movement of the particles in a substance

Answer 79

The amount of energy required to increase the temperature of 1 kg of a substance by 1°C (The diagonal lines of a heating curve)

Answer 80

ΔQ = m x c x Δø Change in energy(J) = mass(kg) x specific heat capacity(J/kg°C) x change in temperature(°C)

Answer 81

* The amount of energy required to change the state of 1kg of a substance (The horizontal parts of a heating curve) * This energy is given out when the doing the opposite state changes are equal to how much it takes * (energy needed for evaporating = energy released form condensing)

Answer 82

Q = m x L Energy = mass x Specific latent heat

Answer 83

* Time on x-axis temperature on y-axis * There will be a diagonal line going up steadily upwards * Eventually it will plateau and be a horizontal line for a bit * It will then continue to rise diagonally then plateau and then rise once more * The diagonal lines are where energy is transferred and stored as thermal energy and increasing the temperature * During the plateaus, the energy is being used to overcome the forces that hold the molecules together resulting in changes of state

Answer 84

* A measure of the average kinetic enegry of the particles in the gas * By heating it up (providing thermal energy) the particles will start to move faster meaning a higher temperature

Answer 85

* A higher temperatures means that the particles in the gas are moving fatser. * This means that they will have more frequent collisions with the walls of their container. * This means that the force exerted on the container is higher leading to a higher temperature.

Answer 86

pascals (Pa) [where 1 Pa = 1 N/m²]

Answer 87

* Once the temperature of a gas has reduced to -273°C (or 0K) then the particles in the gas have a pressure of 0 meaning they aren't moving. * This is only theoretical as gases would normally condense to a liquid once reaching this low a temperture

Answer 88

* The kelvin scale has the same intervals as celcius but 0 K is equal to absolute zero (-273°C) * To convert K - °C - 273 and °C - K + 273

Answer 89

Directly proportional

Answer 90

When gas particles hit a surface, they produce a net force acting at right angles to the surface. We detect this as gas pressure

Answer 91

* Inside a container, the pressure acts at right angles to the walls * If the same number of particles are in a smaller space, they will hit the walls of the container more often * This means the force on the walls increases. We detect this as a higher pressure

Answer 92

* P₁ x V₁ = P₂ x V₂ * This means that an increase in pressure or volume will cause a decrease of the other by the same proportion * They are inversely proportionate

Answer 93

* More air is forced into the typre when you pump it * This increases the number of gas particles in a fixed volume * As a result, there is an increase in the frequency of collisions between gas particles and the (inner) surface of the tyre * This leads to more force exerted on and thus an increased pressure in the tyre

Answer 94

* Each time you push the pump handle, the force is transferring energy to the gas inside the pump (This is work done) * As the piston of the bike pump moves, the speed (KE) of any particles inside the particles increases as they bounce off it * This means that the average speed of the particles has increased and we detect this as an increase in temperature

Answer 95

* Change shape(/size) * Change direction * Accelerate (Decelerate)

Answer 96

It is called deformation and requires two forces rather than just one.

Answer 97

The forces change the object's shape but it returns back to its original shape when forces are removed. (e.g spring, diving board, and archer's bow.)

Answer 98

The forces change the object's shape and it doesn't return back to its original shape when forces are removed. (e.g Clay, Blu-tac, and spoons.)

Answer 99

Some objects (like springs for example) will behave elastically. However, when the forces exceed a certain amount, they will become permanently deformed, behaving inelastically and keeping its new shape. [Life Lesson #44: Don't overextend yourself]

Answer 100

The change in length of a spring when a force is applied New length - old length = extension

Answer 101

* It is a linear relationship (straight line) as long as the spring behaves elastically. * Once it is permanently deformed, the relationship is non-linear (curved).

Answer 102

* Spring: They are directly proportional as it would be a straight line through the origin. * Elastic band: It behaves completely inelastically with a non-linear relationship

Answer 103

The force (N) required to produce and extension of 1 metre

Answer 104

F = k × x Force (N) = Spring constant (N/m) × Extension (m)

Answer 105

F ∝ x(Directly proportional)

Answer 106

Sign gradient is Δy÷Δx it would be force/extension which will give you the spring constant of a spring

Answer 107

Stiffer springs have a higher spring constant (As they require more force to extend)

Answer 108

E = 1/2 × k × x² Energy transferred by stretching (J) = 1/2 × Spring constant × Extension²

Answer 109

* Set up your equipment as shown * Measure the length of the spring without any weights at eye-level * Add 1 newton (100g) weights one at a time, measuring the new length at eye level each time * Take away the original length from all your values to get the extension * Repeat a few times and take the average of your results for reliability * Plot a graph of force/extension and calculate the gradient of the line. This will be the spring constant * If you want to find the work done for a particular extension, square that extension, divide by 2 and then multiply by the spring constant

Answer 110

P = F ÷ A Pressure (Pa) = Force [normal to surface] (N) ÷ Area of that surface (m²)

Answer 111

Pa - Pascals, which is equivalent to N/m² (however the m in N/m² can be changed to any other metric length value but won't be equal to 1 Pa)

Answer 112

Liquids or gases | (Because they f̶l̶o̶o̶o̶d̶ flow)

Answer 113

The pressure exerted perpendicular to any surface by the air at all times. It is highest at sea level around 100,000 Pa (1 atm)

Answer 114

* Depth of the fluid: The more particles above you, the higher pressure you will experience as more particles can produce a higher force. This is why pressure is highest at sea level and reduces as you increase altitude * Density of fluid: The denser the fluid you are in, the more particles there are in a fixed volume, the more particles can produce a force. This is why water pressure is higher than air pressure

Answer 115

Find the pressure exerted by the water and add 100,000 Pa of air pressure

Answer 116

* When sealed at sea level, the air inside the bag will around 100,000 Pa * When taken to a higher altitude, the pressure outside the bag decreases * As the pressure inside the bag (acting outwards) is greater than outside the bag (acting inwards), the bag expands

Answer 117

P = h × ρ × g Pressure [due to column] (Pa) = height of column (m) × density of fluid (kg/m) × gravitational field strength (N/kg)

Answer 118

The upward force exerted on the bottom of an object in a liquid.

Answer 119

Difference in pressure between top and bottom of the object multiplied by the surface area of the bottom of the object [Upthrust = Δh × ρ × g × surface area (m²)] OR Upthrust is the weight (in Newtons) of the liquid displaced when an object is placed in the liquid

Answer 120

The density of the object is less than the liquid it is in. The lower the density, the better it floats (more will be above the liquid surface)

Answer 121

A magnet that always has a magnetic field

Answer 122

A magnet material that only has a magnetic field when in the field of another magnet.

Answer 123

It is now an induced magnet

Answer 124

* Iron * Steel * Nickel * Cobalt

Answer 125

A plotting compass

Answer 126

A uniform parallel magntic field

Answer 127

* They are going form north to south, increasingly spaced out the further away from the magnet. * They go in curves around the outside

Answer 128

* It has field lines similar to that of a bar magnet around it. * We can see this through compasses. * It is a core made of nickel and iron.

Answer 129

Its geographic north pole is its magnetic south pole and vice versa

Answer 130

The direction of the current

Answer 131

* Curl your right hand into a fist and stick out your thumb. * Point your thumb in the direction of the current and the direction your finger curl aorund is the direction of the magnetic field?

Answer 132

* Cross means that the current is haeding away from you * Dot means the current is going towards you

Answer 133

A solenoid

Answer 134

A bar magnet

Answer 135

A uniform parallel field

Answer 136

An electromagnet

Answer 137

* Adding an iron core (a temporary magnet) * Increasing the current

Answer 138

* The strength of the current (Stronger when higher) * The distance from the wire (stronger when closer)

Answer 139

When a wire carrying a current enters a uniform parallel magnetic field

Answer 140

The magnetic field from the wire acting against the magnetic field from the uniform parallel field produces a force that acts on the wire.

Answer 141

**The left hand rule**: * Set your hand so your thumb is up and your first and second fingers are at right angles. * Your first finger represents the direction of the field. * Your second finger represents the direction of the current. * Once these are lined up, the way your thumb is pointing will be direction of the force

Answer 142

F = B I L Force (N) = Magnetic field strength (T) x Current (A) x Length of wire inside the UP field (m)

Answer 143

Magnetic flux density: * T - Telsa * N/Am - Newton per amp metre

Answer 144

* The motor effect is set up so that the wire returns back to where is started. * This means there are two sections of the wire inside the UP field with current travelling in different directions in each. * This means that the direction of force on one will be up and down on the other. * The wires are centered around a pivot which allows these forces to cause a turning motion. * This is the motor effect.

Answer 145

* Once the side of the motor's wire that is moving upwards has made a half turn it will be on the other side but still experiencing an upward force. * This would mean that the motor keeps spinning back and forth around that point without ever making a full turn. * The SR commutator means that once it has made a half turn the current will be 'reset' and change direction so the wire that was previously having a current going forward will now have it going back. * So the wire experiencing an upward force will now experience a downward force and vice versa.