GCSE AQA Physics P1

What is a system in physics?

An object or group of objects

What is a closed system?

A system where no energy or matter can enter or leave

What is the net change in total energy in a closed system?

Zero

What is kinetic energy?

The energy stored in moving objects

What energy store is added to when an object is lifted upwards?

Gravitational potential energy store

What energy store increases when a spring is stretched or compressed?

Elastic potential energy store

What energy store is associated with the temperature of an object?

Thermal energy store

What energy store is released from chemical bonds during reactions?

Chemical energy store

What energy store is released when atomic nuclei split or fuse?

Nuclear energy store

What energy store is associated with two separated electrical charges?

Electrostatic energy store

What energy store is associated with two separated magnetic poles?

Magnetic energy store

Name the energy pathway when a force moves an object through a distance

Mechanical work

Name the energy pathway when a charge moves through a potential difference

Electrical work

Name the energy pathway when energy moves due to a temperature difference

Heating

Name the energy pathway when energy moves via light, sound, or microwaves

Radiation

Describe the main energy transfer when a ball is thrown upwards

Chemical store of the arm to kinetic store of the ball to gravitational potential store of the ball

Describe the main energy transfer when a falling object hits the ground without bouncing

Kinetic store of the object to thermal store of the object and surroundings

Describe the main energy transfer when a car brakes to a stop

Kinetic store of the car to thermal store of the brakes and surroundings via mechanical work

Describe the main energy transfer when an electric kettle boils water

Electrical pathway to thermal store of the heating element and water

State the equation for kinetic energy

Kinetic energy = 0.5 x mass x speed^2

What symbol represents kinetic energy in equations?

Ek

What is the SI unit for energy?

Joules (J)

What is the SI unit for mass in physics equations?

Kilograms (kg)

What is the SI unit for speed?

Metres per second (m/s)

How do you convert grams (g) into kilograms (kg)?

Divide by 1000

How do you convert kilometres per hour (km/h) into metres per second (m/s)?

Divide by 3.6

State the equation for gravitational potential energy

Gravitational potential energy = mass x gravitational field strength x height

What symbol represents gravitational potential energy?

Ep

What is the standard value of gravitational field strength (g) on Earth?

9.8 N/kg

What is the SI unit for height in physics equations?

Metres (m)

State the equation for elastic potential energy

Elastic potential energy = 0.5 x spring constant x extension^2

What symbol represents elastic potential energy?

Ee

What is the SI unit for spring constant?

Newtons per metre (N/m)

What is the SI unit for extension in Hooke's Law?

Metres (m)

What is meant by the limit of proportionality of a spring?

The point beyond which extension is no longer directly proportional to force

What happens to a stretched material if it deforms elastically?

It returns to its original length when the force is removed

What happens to a stretched material if it deforms plastically?

It stays permanently deformed when the force is removed

State the equation linking change in thermal energy, mass, specific heat capacity and temperature change

Change in thermal energy = mass x specific heat capacity x temperature change

What is the symbol used for specific heat capacity?

c

What is the definition of specific heat capacity?

The amount of energy required to raise the temperature of 1 kg of a substance by 1 degree Celsius

What is the SI unit for specific heat capacity?

Joules per kilogram per degree Celsius (J/kg°C)

What symbol represents temperature change in physics equations?

Delta theta (Δθ)

What piece of apparatus is used to measure the mass of a block in the specific heat capacity practical?

A digital balance

Why is insulation wrapped around the metal block in Required Practical 1?

To reduce thermal energy loss to the surroundings

Why is a few drops of oil placed in the thermometer hole in Required Practical 1?

To improve thermal contact between the block and the thermometer

What two electrical meters are used to determine electrical power supplied to the heater in Required Practical 1?

A voltmeter and an ammeter

State the equation used to calculate electrical power supplied to the heater in Required Practical 1

Power = potential difference x current

State the equation used to calculate energy supplied by the heater over time t

Energy = power x time

Why should you wait a short time after switching off the heater before recording the maximum temperature in Required Practical 1?

To allow thermal energy to conduct evenly throughout the block

Why is the measured specific heat capacity often higher than the true textbook value in Required Practical 1?

Some thermal energy is lost to the surroundings instead of heating the block

What is the definition of power?

The rate at which energy is transferred or the rate at which work is done

State the equation for power in terms of energy transferred

Power = energy transferred / time

State the equation for power in terms of work done

Power = work done / time

What is the SI unit for power?

Watts (W)

What is one Watt equivalent to?

One Joule per second (1 J/s)

How do you convert kilowatts (kW) into Watts (W)?

Multiply by 1000

If Motor A lifts a mass in 5 seconds and Motor B lifts the same mass in 10 seconds, which motor has higher power?

Motor A because it transfers the same energy in less time

State the Law of Conservation of Energy

Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed

What is meant by dissipated energy?

Energy that is transferred to non-useful thermal stores and wasted to the surroundings

How does friction cause energy dissipation?

It converts kinetic energy into non-useful thermal energy transferred to the surroundings

How can unwanted friction in moving mechanical parts be reduced?

By applying a lubricant

What is thermal conductivity?

A measure of how rapidly a material conducts thermal energy

How does thermal conductivity affect the rate of energy transfer across a material?

A higher thermal conductivity results in a higher rate of energy transfer by conduction

How do double-glazed windows reduce thermal energy loss in a house?

The vacuum or dry air trapped between the glass panes has a very low thermal conductivity

How does cavity wall insulation reduce thermal energy transfer in homes?

Trapped air inside the foam reduces energy transfer by conduction and convection

What is the independent variable when testing different insulating materials in Required Practical 2?

The type of insulating material wrapped around the container

What is the dependent variable in Required Practical 2 (Thermal Insulation)?

The temperature drop of the water over a set time period

Name three control variables in Required Practical 2 (Thermal Insulation)

Volume of water, starting temperature of water, and time duration

Why must a lid be placed on the beaker during Required Practical 2?

To prevent thermal energy loss by evaporation and convection from the top surface

What is the independent variable when testing the effect of insulation thickness in Required Practical 2?

The number of layers of insulating material

How does increasing the number of insulation layers affect the cooling rate of hot water?

It decreases the cooling rate because thermal energy transfer by conduction is reduced

State the equation for efficiency in terms of energy

Efficiency = useful output energy transfer / total input energy transfer

State the equation for efficiency in terms of power

Efficiency = useful power output / total power input

How can efficiency be expressed?

As a decimal (between 0 and 1) or as a percentage (between 0% and 100%)

Why can no device or machine be 100% efficient?

Some energy is always dissipated to non-useful thermal stores due to friction or electrical resistance

How can the efficiency of an electric motor be increased?

Lubricate moving parts and use low-resistance copper wires

How can the energy efficiency of a house heating system be increased?

Insulate walls and roof, use double glazing, and draught-proof doors and windows

What is a renewable energy resource?

An energy resource that is replenished as fast as it is used and will not run out

What is a non-renewable energy resource?

An energy resource that is used up faster than it can be replenished and will eventually run out

Name three main non-renewable fossil fuels

Coal, oil and natural gas

What non-renewable fuel is used in nuclear power stations?

Uranium or plutonium

Name seven renewable energy resources

Solar, wind, hydroelectricity, geothermal, tidal, wave and biofuel

Which three main energy resources are used for transport?

Oil (petroleum/diesel), biofuels, and electricity

Which four main energy resources are used for domestic heating?

Natural gas, coal, biomass/wood, and electricity (geothermal/solar water heating)

Give two advantages of fossil fuels

Reliable power generation and high energy density

Give three disadvantages of fossil fuels

Releases carbon dioxide causing global warming, releases sulfur dioxide causing acid rain, and non-renewable

Why does burning fossil fuels cause global warming?

It releases greenhouse gases like carbon dioxide which trap heat in the atmosphere

Why does burning coal produce acid rain?

Coal contains sulfur impurities that burn to form sulfur dioxide gas

Give two advantages of nuclear power

No greenhouse gas emissions during operation and highly reliable continuous power output

Give three disadvantages of nuclear power

Produces dangerous radioactive waste, high decommissioning costs, and long setup times

Give two advantages of wind energy

Renewable resource and produces no greenhouse gas emissions during operation

Give three disadvantages of wind turbines

Unreliable as output depends on wind, visual and noise pollution, and high initial setup cost

Give two advantages of solar cells

Renewable resource and requires no fuel or running costs

Give two disadvantages of solar power

Unreliable as it does not work at night or on cloudy days, and requires large surface areas

Give two advantages of hydroelectric power

Highly reliable with immediate response to peak electricity demand

Give two disadvantages of hydroelectric dams

Floods vast areas destroying natural habitats, and releases greenhouse gases from rotting vegetation

Give an advantage of geothermal energy

Reliable power source available 24/7 in volcanically active regions

Give a disadvantage of geothermal energy

Suitable locations are limited to volcanically active areas

Give an advantage of tidal power

Highly predictable energy generation schedule based on ocean tides

Give two disadvantages of tidal barrages

Can block boat navigation and damages marine wildlife habitats in estuaries