Physics

Question 1

Units of measurement
Power Time Distance Energy Force Weight Pressure Spring constant Moment Momentum

Answer 1

-Power(W) -Time(s) -Distance(m) -Energy(J) -Force(N)
Weight(N) -Pressure(Pa) -Spring constant(N/m) -Moment(Nm) -Momentum(kg m/s)

Question 2

Energy stores

Answer 2

Thermal, Gravitational potential, Elastic potential, Magnetic, Chemical, Electrostatic, Nuclear, Kinetic

Question 3

Energy transfer

Answer 3

Mechanical, Electrical, Heating, Radiation

Question 4

Specific heat capacity

Answer 4

Amount of heat required to raise 1kg of a substance by 1 degree

Question 5

Internal energy

Answer 5

Potential energy + Kinetic energy

Question 6

Heat transfer

Answer 6

Conduction: Solid (Vibrating particles collide with neighbouring particles
Convection: Fluids (Particles with more thermal energy diffuse faster to cooler regions)
Radiation: Empty space (Infrared waves emitted from hot objects)

Question 7

Renewable energy sources

Answer 7

Wind, Solar, Hydroelectricity, Geothermal, Biofuels

Question 8

Wind energy

Answer 8

Turbines use blades to turn a generator which converts kinetic energy to electricity

Question 9

Geothermal energy

Answer 9

Thermal energy in the earth’s crust that can only be harnessed in areas like volcanoes

Question 10

Biofuels

Answer 10

Made from recently living organisms like plants, however, CO2 is released into the environment

Question 11

Hydroelectricity

Answer 11

Produced using dams which harness the gravitational potential energy of the upstream water using generators to generate electricity

Question 12

GO OVER ELECTRICAL SYMBOLS

Answer 12

https://docs.google.com/document/d/1szHhVQkR3bQfcthR0SFJPBzoNhPYe_dNQyYS6zxB7bE/edit?tab=t.0

Question 13

Diodes
Fuses
LED
Variable resistor
LDR
Thermistor

Answer 13

Diode- Allows flow in one direction
Fuse- Breaks if too much current flows
LED- Emits light if current flows in forward direction
Variable resistor- Resistance can be modified
LDR- Decreases resistance the lighter it is
Thermistor- Decrease resistance the hotter it is

Question 14

Conventional current

Answer 14

Current flows from the positive terminal (big line) to the negative terminal (small line)

Question 15

Charge

Answer 15

Total current flowed within a period of time measured in Coulombs (Q)

Question 16

Parallel circuit (vs series)

Answer 16

Voltmeter (vs Ammeter)
Each component gets a total Pd (vs Pd is shared across components)
Current is shared across loops (vs current is the same everywhere)
More loops= lower resistance (vs total resistance=sum of resistance of individual components

Question 17

National power grid

Answer 17

Uses high voltage and low current because it is more efficient than using high current which causes thermal energy waste as resistance. It uses power stations which burn fossil fuels to produce thermal energy which they use to evaporate water into steam for turning turbines. It uses step up transformers towards the pylons and step down transformers towards houses

Question 18

Alternating current

Answer 18

Constantly swaps direction of flow using alternating voltage. Induces an alternating magnetic field in the iron core which induces an alternating current in the secondary coil Hz measures the amount of times it swaps a second

Question 19

Plug

Answer 19

Left wire is blue and neutral to complete circuit
Middle wire is green and yellow and the earth wire dissipates excess energy in the casing
Right wire is brown and live to carry current from the power supply to the appliance. It is connected to a fuse
They are all enclosed in an outer insulation which is held in place using cable grips

Question 20

Surges

Answer 20

Sudden increases in voltage which can be dealt with using circuit breakers or fuses. Circuit breakers merely turn off the circuit when trippe

Question 21

Static electricity

Answer 21

Build up of charge on the surface of insulators which is caused by the electrons transferring across insulators but not being able to enter via conduction, therefore, when Pd becomes great enough they can leap to the floor creating a shock.

Question 22

Ionisation

Answer 22

Occurs when strongly charged fields attract electrons from neutral atoms like air causing them to become positively charged

Question 23

Electromagnetic forces

Answer 23

Get stronger closer to the particle and field lines always go from positive to negative causing attraction and repulsion

Question 24

Gases in a container

Answer 24

If gas is trapped in a container with a fixed volume then the pressure will increase else the volume of gas else the volume will increase in an expandable container

Question 25

Unit conversions

Answer 25

If a unit conversion involves indices such as cm² -> m², just multiply the scale factor by the indice so for the example you would divide the cm by 100² or 10000.

Question 26

Temperature time graph

Answer 26

The line moves up or down gradually but plateaus at certain points. These points can be used to find specific latent heat because where the temperature stays the same it is using the internal energy for a change in state.

Question 27

Radioactive material

Answer 27

Has unstable isotopes which can decay into other elements by emitting radiation.

Question 28

Alpha radiation (a)

Answer 28

2 protons, 2 neutrons, 0 electrons so +2 charge like He nucleus Large so strongly ionising but can't travel far and are absorbed easily

Question 29

Beta radiation (B)

Answer 29

Neutron -> Proton + Beta Particle (Electron) Tiny so travel further and are hard to absorb but they are moderately ionising

Question 30

Gamma radiation (y)

Answer 30

Waves of electromagnetic radiation Can travel very far and are very hard to absorb but they are weakly ionising

Question 31

Activity

Answer 31

The rate of decay measured in becquerels (Bq) using a Geiger Muller counter. Half life is the amount of time it takes for the activity or the radioactive nuclei to halve

Question 32

Irradiation vs contamination

Answer 32

Irradiation is when an object is exposed to radiation become irradiated leading to DNA becoming ionised leading to mutations like cancer. Whereas contamination is when radioactive material gets on the surface of an object which isn't dangerous unless it decays and irradiates the object

Question 33

Uses of radiation

Answer 33

Radiotherapy uses beta or gamma radiation from the outside to destroy cancerous particles although this damages healthy cells leading to hair loss and sickness Medical tracers work by injecting mainly gamma tracers so they emit radiation allowing gamma cameras to pick up movement and how the body is functioning

Question 34

Nuclear fission

Answer 34

Splitting up an unstable nuclei such as Uranium 235 into 2 daughter nuclei releasing huge energy and 2 or 3 neutrons in the process. This can happen naturally or by absorbing a neutron, however, to harness the second method safety measures must be taken. Nuclear reactors use control rods which are lowered down to absorb neutrons slowing the rate of the reaction. The energy from this reaction is then converted to electricity similar to in power grids. This is cheap and environmentally friendly, however, it is unrenewable and could have devastating malfunctions

Question 35

Nuclear fusion

Answer 35

Fusion of 2 light nuclei to form a heavy nucleus releasing tons of energy, however, this can only occur under extremely hot conditions like stars

Question 36

Specific heat capacity RQ

Answer 36

1. Place beaker on scales 2. Add oil to beaker and record mass of oil 3. Measure temperature on thermometer 4. Wrap the beaker in insulating foam 5. Connect beaker to immersion heater and leave for 30 minutes 6. Find temperature and do calculation to find specific heat capacity

Question 37

Thermal insulators RQ

Answer 37

1. Place small beaker in large beaker 2. Boil water using kettle and pour into small beaker 3. Cover both beakers with a lid and place a thermometer through a hole 4. Record starting temperature and start stopwatch 5. Record temperature every 3 minutes for 15 minutes 6. Repeat with different insulating materials inside the gap between the two beakers

Question 38

Resistance RQ

Answer 38

1. Connect battery to an ammeter and then connect ammeter to crocodile clip which connects to wire along a ruler which then connects back to circuit using another crocodile clip. Connect Voltmeter in parallel to crocodile clips 2. Take reading from voltmeter and ammeter 3. Repeat incrementing length of wire by 10cm until 1m 4. Use equation to find resistance

Question 39

Current/Pd characteristics RQ

Answer 39

1. Connect a battery to an ammeter to a resistor to a variable resistor. Connect voltmeter in parallel to resistor 2. Take readings from voltmeter and ammeter 3. Adjust variable resistor and repeat several times 4. Swap direction of battery to get negative values IV graphs show resistance. If the line is straight the circuit only has resistors or wires because the resistance stays constant. If the line slowly rises in a curve and then slowly plataeus in a curve then the graph shows the resistance in a filament lamp because the heat gradually increases resistance. If the line is a curve which starts at the origin then the circuit contains a diode because it doesn’t allow current to flow in the other direction

Question 40

Density RQ

Answer 40

Weigh object using scales and then find volume using measurements or a Eureka Can. Fill Eureka Can with water up to outlet and place measuring cylinder next to it. Then place object in water and take volume in measuring cylinder