Nov + Mar PPEs + GCSE paper 1 Flashcards

Question

How do you calculate energy transferred?

Answer 1

E = QV | Rearrangement of p.d. equation.

Answer 2

Voltmeters measure volts and are always connected in parallel to components.

Answer 3

The rate of flow of charge, measured in Amps.

Answer 4

current (A) = charge (C) / time (s) | I = Q/t

Answer 5

Q = It | The current equation rearranged.

Answer 6

Ammeters measure amps and are always connected in series with a component.

Answer 7

The measure of how much a component/object resists the flow of current. Measured in Ohms.

Answer 8

Find a point on an IV graph on the line and rearrange Ohm's law.

Answer 9

There is a straight line through the origin meaning V & I are directly proportional. There is a constant gradient and so constant resistance. Due to this, it is 'ohmic'. | (an ohmic conductor) ## Footnote If another resistor gives a steeper gradient, it must have a lower resistance.

Answer 10

The line curves, meaning the resistance isn't consistent. A larger current results in an increased resistance. Due to this, it's non-ohmic.

Answer 11

Delocalised electrons colide with the ionic lattice, which causes them to vibrate more and the temperature increases.

Answer 12

Diodes only let current flow in one direction. There's **low** resistance in the **forward** direction and **high** resistance in the **reverse** direction.

Answer 13

1. Create a circuit with a cell, variable resistor, voltmeter & fixed resistor and ammeter. 2. Use voltmeter to read the p.d. across the resistor 3. Use the ammeter to read the current through the resistor and record the values in a table 4. Adjust the variable resistor and record new readings on the voltmeter and ammeter (must be done several times to get a range of readings) 5. Switch direction of battery, switching the direction of the P.D. - the voltmeter and ammeter should have negative values (repeat step 3) Repeat steps 2-5 with a circuit that has a [cell, variable resistor, voltmeter & filament lamp and ammeter] and a circuit that has a [cell, variable resistor, voltmeter & diode, millammeter and extra resistor]. | The parts of the list written A&B mean A and B are in parallel.

Answer 14

p.d. (V) = resistance (Ω) * current (A) | V = IR

Answer 15

Reverse the cell within a circuit.

Answer 16

- Total p.d. is shared between all components - Current is the same for all components - Total resistance = sum of resistance

Answer 17

- If resistors are identical, total V must be shared equally. - If not, the bigger resistance takes the bigger share of voltage.

Answer 18

- p.d. for each branch = p.d. of cell/battery - current is split between the branches - adding **more resistors in parallel** reduces the total resistance (this is because current has more routes, so flows faster)

Answer 19

- Temp increases - R of thermistor decreases - Thermistor gets a smaller share of the total voltage - The resistor gets a bigger share of the total voltage - Voltmeter reading increases which could be used to turn off heating

Answer 20

- Light intensisty decreases - R of LDR increases - LDR gets a bigger share of total voltage - Voltmeter reading increases, which could be used to trigger a light to turn on

Answer 21

Potential divider circuits to detect changes in the environment.

Answer 22

power = current * p.d OR power = current² * resistance

Answer 23

It's a p.d. that only acts in one direction that results in direct current.

Answer 24

Mains electricity - Alternating current resulting from an alternating P.D.

Answer 25

The blue wire that goes through the left - it's kept at 0V by the electrical company.

Answer 26

The brown wire which goes through the right. It changes between positive and negative potentials and carries the high voltage.

Answer 27

The green and yellow wire, goes through the middle - it's a safety feature. It acts as an 'escape route' for the currents that would otherwise cause shock if the appliance is touched. | It's not mandatory nor necessary for double insulated appliances.

Answer 28

It's a thin metal wire in a tube that's designed to melt or 'blow' if there's a fault that causes a high current. It's always attached to a live wire.

Answer 29

Power station -> step-up transformer -> national grid cables -> step-down transformer -> homes/businesses.

Answer 30

A step up transformer to increase the voltage, decreasing current and reducing power lost due to heating in cables and a step down transformer to reduce the voltage down to a safer and usable voltage. | (If P in = P out, V&I are inversely proportional.)

Answer 31

The charge that remains while electrons are transferred between insultating materials.

Answer 32

- Objects are negatively charged when an object gains electrons - Objects are positively charged when an object loses electrons (like an ion)

Answer 33

Opposite charges attract, like repel. | Charges are straight.

Answer 34

- An electric field is a physical field that surrounds electrically charged particles such as electrons. - It is represented by lines around the charged object: the direction of the arrows show what the force would be on a positive charge if it was placed in the field. ## Footnote The field lines always go from positive to negative.

Answer 35

- A radial field - The field lines diverge the further from the charged object: the field gets weaker - This can be seen in a Van Der Graaff generator

Answer 36

How compact mass is for an object.

Answer 37

ρ = m/v density(kg/m³) = mass(kg)/volume(m³) | ρ is the greek letter 'ro'

Answer 38

- Find the mass using a top-pan balance and record it - Volume can be calculated by taking the measurements with a ruler (resolution 1mm) and doing the following calculation: area\*length - Then use ρ = m/v

Answer 39

- Find the mass using a top-pan balance and record it - Find and fill a displacement can with water to the spout. - Carefully and slowly submerge object in water (using string) and wait for all water to be displaced out into a beaker placed at the spout - Pour water within beaker into a measuring cylinder and take volume by getting on eye-level and using the bottom of the meniscus line - Calculate density using ρ = m/v

Answer 40

- Particles are in a regular arrangement - Particles vibrate at fixed positions - They can't be compressed

Answer 41

- Particles arranged in an irregular arrangement - Particles can move past each other - They can't be compressed.

Answer 42

- Particles are far apart - They can move past each other and collide - Particles move quickly - They can be compressed

Answer 43

Energy must be supplied to overcome the electrostatic forces of attraction between particles.

Answer 44

Solid -> liquid: melt Liquid -> gas: evaporate

Answer 45

Gas -> liquid: condensing Liquid -> solid: freezing

Answer 46

Solid -> Gas: sublimation Gas -> Solid: deposition

Answer 47

The sum of kinetic energy and potential energy of all particles in a substance. Only one changes at any time.

Answer 48

When the temperature rises, the kinetic energy in particles rises. When temperature is static, the potential energy rises.

Answer 49

It's being used to overcome the electrostatic forces of attraction between particles.

Answer 50

Same as SHC/thermal energy equation. △thermal energy(J) = mass(kg)\*specific heat capacity (J/kg°C)\*△temperature(°C)

Answer 51

Specific Heat Capacity - the energy required to raise the temperature of 1kg of a substance by 1°C. | e.g. 4200J/kg°C for water.

Answer 52

E = mL Potential energy (J) = mass (kg)\*specific latent heat(J/kg)

Answer 53

Specific Latent Heat - the energy required to change the state of 1kg of a substance. | e.g. SLH of fusion for water is 334000J/kg

Answer 54

The result of gas particles colliding with the walls of its container, exerting outward force.

Answer 55

It increases the gas particles' kinetic energy, meaning they collide more frequently and with a greater force. This raises pressure.

Answer 56

Exert a force on it and raise pressure through turning up the temperature.

Answer 57

Pressure and volume are inversely proportional. When one doubles, the other halves. The equation to show this is pV = constant pressure (N/m²)*volume(m³) Thanks to this; p₁V₁ = p₂V₂

Answer 58

- Ancient Greeks: matter was made of indivisble particles - JJ Thomson: Plum pudding model - Ernest Rutherford: Discovered the nucleus was small and postively charged by finding that most alpha particles went straight through a gold "leaf": very few deflected back - Neils Bohr: Electrons exist in 'shells'/'energy levels' - James Chadwick: Nucleus must contain neutrons as well as protons

Answer 59

- Protons: +1, 1 - Neutron: 0, 1 - Electrons: -1, 1/2000 | Subatomic particle: Charge, mass

Answer 60

They decay (emitting radiation. Radiation can ionise other atoms/molecules which can be dangerous.)

Answer 61

A high energy EM wave that can be emitted by a nucleus. This isn't due to decay but due to the nucleus having excess energy.

Answer 62

The decay of larger nuclei which ejects a helium nucleus (2 protons + 2 neutrons). A helium nucleus is an alpha particle. | Alpha particles are represented by ⁴₂He

Answer 63

The decay of smaller nuclei into a proton and an electron. The proton is kept but the electron is the beta particle which is emitted. | Beta particles are represented by ⁰₋₁e⁻ ## Footnote After beta radiation, the nucleus subjected to it gains a proton, while mass goes unchanged.

Answer 64

With a Geiger-Muller (GM) tube touching it. It's important as ionisation can be dangerous for living things.

Answer 65

- Cosmic rays - Radon gas - Nuclear weapons - Medical equipment When measuring radiation, background count should be taken first, then subtracted from the count of bg radiation to give the correct count.

Answer 66

Neutrons can also be ejected from nuclei under certain conditions; which can then be absorbed by the nuclei of the target object making it unstable.

Answer 67

- Ionising power: high - Penetrating ability: low (absorbed by paper/few cm of air) - Use: smoke detectors

Answer 68

- Ionising power: medium - Penetrating ability: medium (absorbed by a few mm of aluminium) - Uses: thickness gauge

Answer 69

- Ionising power: low - Penetrating ability: high (intensity reduced by lead and concrete) - Uses: Radiotherapy and gamma knife & sterilisation

Answer 70

The rate of decay in a sample of radiactive material, equal to the rate of radiation emitted.

Answer 71

A Becquerel (Bq) which basically the same as c.p.s (counts per second) detected.

Answer 72

The time it takes for the activity to halve. No matter the start number, it'll always take the same amount of time for it to halve.

Answer 73

The splitting of a heavier nucleus into two nuclei, decreasing total mass and releasing energy (mostly kinetic/heat) that can be used to generate electricity. Fission is induced by a nucleus absorbing a neutron, making it more unstable. ## Footnote The total mass of the nucleus/nuclei has actually been converted into energy!!

Answer 74

- Fission releases up to 3 more neutrons - They induce more fission Unchecked, it can cause the same destruction as an atomical nuclear bomb. Controlled, in a nuclear reactor it releases loads of energy which can be used to produce electricity.

Answer 75

* The joining together of two lighter nuclei releasing energy (kinetic and EM radiation). * It happens in the sun but it's difficult to harness the energy by fusion in the reactors being developed.

Answer 76

Pascals (Pa) which is the same as N/m²

Answer 77

Contact and non-contact.

Answer 78

Friction, air resistance and tension.

Answer 79

Magnetism, electrostatic force and gravity.

Answer 80

A quantity with only magnitude. (distance, speed, and temperature)

Answer 81

A quantity with a magnitude AND direction. (displacement, velocity and acceleration)

Answer 82

The sum of the 2 (or more) forces acting on an object. If 2 forces are at a right angle, use pythagoras' theorem or trigonometry. | remember for trig: SOH CAH TOA!!

Answer 83

A force that doesn't change velocity and has no resultant force.

Answer 84

The force that gravity pulls an object down with.

Answer 85

Weight (N) = mass(kg)\*gravitational field strength(N/kg) W = mg

Answer 86

The same as its weight.

Answer 87

Work done(J) = force(N)\*distance(m) | W = Fd

Answer 88

Energy transferred by a force.

Answer 89

The force and extension of an object which deforms elastically are directionally proportional.

Answer 90

Force(N) = spring constant(N/m)\*extension(m) F = ke

Answer 91

1. Set up a clamp and stand with a spring hanging off the clamp and a mass hanger attached. Place a ruler parallel to the stand. 2. Add masses onto the spring to change force in 1N increments. 3. Measure the extension of the spring with the ruler after each mass is added. 4. Plot results on a graph. Gradient = Spring Constant.

Answer 92

- There can be a systematic error with measuring. Avoid it by lining up 0cm with the bottom of the spring. - There can be a random error by misreading the ruler due to perspective. Avoid this by getting eye level with the measurement when measuring.

Answer 93

A turning force. moment (Nm) = force (N) * distance from pivot (m)

Answer 94

When the sum of clockwise moments = sum of anticlockwise moments a system is in equilibrium.

Answer 95

They can be used to increase moments by driving a large gear with a smaller one (they work on ratios: double the diameter, double the moment or 'torque')

Answer 96

Pressure (N/m² or Pa) = force (N) / area (m²)

Answer 97

This is due to the weight of the water above us pushing down on us.

Answer 98

Pressure (N/m²) = height (m)\*density(kg/m³)\*g(N/kg) P = Lρg

Answer 99

The particles colliding with the walls of its container.

Answer 100

- Decrease the volume and add more gas (creating more frequent collisions) - Increase the temperature (more frequent collisions - faster speed and collide with more momentum - greater force) | To decrease would be the reverse.

Answer 101

The atmosphere gets less dense and there is less pressure.

Answer 102

The gradient. velocity (m/s) = distance or displacement (m) / time (s) | v = d/t

Answer 103

The gradient. acceleration (m/s²) = change in velocity (m/s) / time (s) | a = △v/t

Answer 104

The area under the gradient.

Answer 105

S - displacement(m) U - initial velocity (m/s) V - final velocity (m/s) A - acceleration (m/s²) T - time (s)

Answer 106

* v = u + at * s = (u+v/2)\*t * s = u\*t+0.5\*a\*t² * v²-u² = 2\*a\*s

Answer 107

If no resistant force acts on an object, its motion will be constant.

Answer 108

The tendency for an object's motion to stay constant if there's no resultant force.

Answer 109

An object experiences terminal velocity when the drag force = other force acting on it.

Answer 110

Force (N) = mass (kg)\*acceleration(m/s²)

Answer 111

Accelerate trolley on tract with slotted mass on string over pully - Use photogates to measure acceleration - Change force by removing masses and placing them on the trolley. - Plot force against acceleration. The gradient = total mass.

Answer 112

For every action there's an equal and opposite reaction. This is always true.

Answer 113

Thinking distance + breaking distance.

Answer 114

Speed (proportional), distractions, alcohol, drugs, fatigue.

Answer 115

- Speed (proportional with a ratio of 1:1² because E_k = 0.5\*m\* **v²**) - Condition of brakes, tyres and road - Weather conditions

Answer 116

momentum (kgm/s) = mass (kg)\*velocity(m/s) | momentum = mv

Answer 117

Conserved.

Answer 118

m₁u₁ = m₁v₁ + m₂v₂

Answer 119

m₁u₁ = mv

Answer 120

0 = m₁v₁ + m₂v₂

Answer 121

The measure of the rate of change of momentum.

Answer 122

force = change in momentum / change in time | force = △momentum/△time

Answer 123

As time goes on and momentum is lost or gained, the force exerted is lost and vice versa.

Answer 124

- Seat belts - Air bags - Crumple zones They increase collision time, so momentum is lost over a longer time, reducing force and therefore harm possibly caused.

Answer 125

Waves transfer energy but not matter.

Answer 126

Parallel to the direction of energy transfer.

Answer 127

Perpendicular to the direction of energy transfer.

Answer 128

Compressions and rarefactions.

Answer 129

Sound waves and seismic P waves

Answer 130

Water waves and light waves.

Answer 131

The length of one complete wave. | λ

Answer 132

The time taken for one wave to pass.

Answer 133

The number of waves that pass every second.

Answer 134

wavespeed (m/s) = frequency (Hz) * wavelength (m) | v = fλ

Answer 135

- You will need a ripple tank with white paper beneath it, a lamp above it, water within the tank and a vibrating bar in the water connected to a power pack. - Place a ruler on the paper, and record the ripple tank's shadows as the vibrating bar is on. - Use a frame of the video to measure the distance of 10 wavelengths. Then divide it by 10, giving the wavelength of these waves. - Then mark a point on the paper, place a timer next to the paper and record again for 15 seconds. - Trim the video to 10 seconds and count the number of waves passing the point you marked in that time in slow motion. Then divide by 10, finding the frequency. - Then use the wave equation to find the wave speed. v = f * λ

Answer 136

1. Set up a string attached to a vibration generator and a hanging mass. Hang the mass on with a pulley on a clamp (to keep the string taut) and keep the string level with a wooden bridge. Control the frequency of vibration using a signal generator connected to the vibration generator. 2. A certain frequency, the string becomes a standing wave due to resonance (looks like ♾️) 3. Measure the wavelength of the standing wave using a ruler (the distance between the wood bridge and the vibration generator) 4. Use the wavelength and frequency to calculate the speed of the wave (v = λ\*f) | Wavespeed depends on the taughtness of the string and the mass/cm.

Answer 137

Higher frequency = higher pitch Greater amplitude = louder

Answer 138

The human hearing range is 20Hz - 20kHz. Anything above 20kHz is ultrasound.

Answer 139

Some sound is transmitted, some is reflected.

Answer 140

When sound meets a boundary between two mediums the sound is either transmitted or reflected. Resulting echoes can be timed to build up an image of what's out of view. | Sonar is used for ultrasounds and fish underneath boats.

Answer 141

Longitudinal waves. | e.g. seismic P-waves.

Answer 142

- Seismic P-waves are longitudinal and pass through the centre of the earth. - S-waves are transverse and don't pass through the centre of the earth. - As S and P waves are sent through one end of the earth only P-waves are detected on the other side, suggesting there is a molten (liquid) core within the earth.

Answer 143

Light reflecting off a smooth surface. The angle of reflection is equal to the angle of incidence in relation to the normal.

Answer 144

Light reflecting off a rough surface, scattering it.

Answer 145

- Radio waves - Micro waves - Infra-red - Visible light - Ultra violet - X-rays - Gamma rays

Answer 146

Emitted and absorbed by electrons, except from gamma which is emitted by nuclei.

Answer 147

It can cause an electron to leave its atom, leaving an ion behind. This is ionising radiation. ## Footnote UV, X-rays and gamma rays do this.

Answer 148

- Phones - TV - WiFi

Answer 149

- Cooking (absorbed by water)

Answer 150

Cooking (absorbed by surface).

Answer 151

Tanning. It can cause skin cancer and ionising radiation.

Answer 152

- X-rays can be used for medical scans - Gamma rays can be used for sterilising, medical treatments Both are dangerous as they have ionising radiation.

Answer 153

*pt 1:* A leslie's cube has a shiny metallic surface, a white surface, a shiny black surface and a matt black surface. 1. Fill leslie's cube with hot water 2. Point an infrared detector at each of the four surfaces and record the amount of infrared emitted (must keep same distance between leslie's cube and detector) The matt black emits the most infrared radiation. Then shiny black, white and shiny metallic. *pt 2:* 1. Infrared heater with two metal plates on either side. One plate is shiny metallic and the other is matt black 2. Vaseline has been used to attach a drawing pin to the outer side of each plate 3. Turn on the heater and a timer 4. Record the time it takes for the vaseline to melt and drawing pins to fall off The drawing pin falls off the matt black plate first. Matt black surfaces absorb more infrared radiation than shiny metallic surfaces. ## Footnote Matt black surfaces are the best emitters and absorbers of infrared radiation.

Answer 154

When waves enter a new medium, their speed and angle changes. ## Footnote If the speed decreases, so does wavelength, while frequency is always constant.

Answer 155

It bends towards the normal. This means the angle of refraction will be smaller than the angle of incidence. | And vice versa. If the wave speeds up, it bends away from the normal.

Answer 156

Because the light disperses; the difference wavelengths are refracted different amounts (blue most, red least).

Answer 157

They use refraction to make light rays converge or diverge. There is convex and concave.

Answer 158

They bend light rays towards the principal focus, which is in the middle of the principle focus.

Answer 159

The focal length is the length of the lens, and a convex lens looks like this: ^ | v

Answer 160

- Draw two rays from the top of the object: 1. Straight through the centre 2. Parallel in, then through the principle focus. - If the two rays don't meet, extrapolate through dotted lines backwards and see where they meet that way. - Then draw the image from the principle axis to the point where the rays meet.

Answer 161

Real images can be projected, virtual images can't (as the rays meet on the wrong side of the lens.

Answer 162

- Draw two rays from the top of the object: 1. Straight through the centre 2. Parallel in, then away from the principle focus. - Then extrapolate the 2nd ray backwards. - Draw the image from the principle axis to the point where the rays meet.

Answer 163

- real/virtual - upright/inverted - magnified/diminished

Answer 164

magnification = image height / object height

Answer 165

Different wavelengths of light are absorbed by the retina. An object will appear a certain colour as it reflects those wavelengths and absorbs others.

Answer 166

A theoretical object that perfectly absorbs and emits all wavelengths of radiation (it doesn't reflect radiation). It can be applied to stars and planets as an approximation.

Answer 167

If the rate of absorption is greater than the rate of emission, the temperature increases. However this also increases the rate of emission.

Answer 168

- Mercury - Venus - Earth - Mars - Jupiter - Saturn - Uranus - Neptune | mnemonic: *my very easy method just set up nine planets.*

Answer 169

The milky way, containing many solar systems.

Answer 170

- Nebula: dust particles are attracted by gravity. - Proto star - Main sequence star: pressure from fusion balanced with gravitational pull until nuclear fusion runs out of fuel

Answer 171

- Red giant: outward pressure increases causes it into expand. - White dwarf: fuel has run out - Black dwarf: cooled

Answer 172

- Super red giant: outward pressure increases until it expands - Supernova: produces heavy elements and a new nebula - Neutron star: if very dense - Black hole: so dense, gravity is so strong that light can't even escape.

Answer 173

- Natural satellites = moon - Artificial satellites = space stations These two orbit the earth. - Geostationary satellites orbit above the same point on the equator. e.g. gps, tv, communications

Answer 174

- Orbits are circular - Speed is constant - Direction changing - Meaning velocity is changing - Accelerating but not getting faster

Answer 175

Always acts towards the centre of the orbit.

Answer 176

A right-angle (90°)

Answer 177

- As it gets faster it gets closer to the earth and vice versa. - Used for reconnaissance and weather.

Answer 178

The wavelength of light from distant galaxies is stretched because the galaxies are moving away from us. ## Footnote Further galaxies are MORE red-shifted, meaning they're receding at a greater rate.

Answer 179

- **Red-shift** suggests at one point all our galaxies originated from the same position. - **CMBR** a.k.a. cosmic microwave background radiation is detected from every direction of space, which could be from the matter still cooling down from the Big Bang.

Nov + Mar PPEs + GCSE paper 1 Flashcards

chapters: 1 - 6, 8 - 14 & 16 (209 cards)