P1 Knowledge Builder

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What is the formula for working out kinetic energy?

Kinetic energy \= ½ x mass x speed^2

What is the standard unit for mass?

Kilograms

What is the standard unit for speed?

m/s (meters per second)

What is the standard unit for kinetic energy?

Joules

What is the standard unit for elastic potential energy?

Joules

What is the standard unit for spring constant?

Newtons per metre (N/m)

What is the standard unit for extension in the elastic potential energy equation?

Metres

What is the formula for gravitational potential energy

G.P.E \= mass x gravitational field strength x height

What is the standard unit for gravitational field strength?

N/kg (newtons per kilograms)

What is the standard unit for specific heat capacity?

Joules per kilogram per degree Celsius (J/KgoC)

What is this the definition of:
The amount of energy required to raise the temperature of 1kg of a substance by 1oC

Specific Heat Capacity

What is defined as the rate at which energy is transferred or work is done?

Power

What is the standard unit for power?

Watts

What is the equation that links power, energy transferred and time?

Power \=Energy transferred
Time

What is the equation that links power, work done and time?

Power \=Work Done
Time

What is energy transferred the same as?

Work done

An energy transfer of 1 joule per second is equal to a power of?

1 Watt

If two electric motors both lift the same weight, the same height which will do it faster?

The more powerful one

Energy can be transferred, stored or dissipated but cannot be

Created or destroyed

In what type of system is there no net change to the total energy?

Closed

How can we reduce unwanted energy transfers?

- Lubrication
- Use of thermal insulation

How does increasing the thermal
conductivity of a material affect the rate of energy transfer by conduction?

It increases it

What factors affect the rate of cooling of a building?

- Thickness of walls
- Thermal conductivity of walls

How do you work out efficiency from input and output energy?

Efficiency \=Useful output energy transfer /Total input energy transfer

How do you work out efficiency from power input and output

Efficiency \=Useful power output /Total power input

What are the three main types of fossil fuels?

Coal, Oil, Gas

Name the main non-renewable energy resources?

Fossil fuels, Nuclear fuel

Name 6 renewable energy resources

Biofuel, Wind, Hydro-electricity,
Geothermal, Tidal, Solar, Water waves

What type of resource is one that is being replenished as it is used?

Renewable

What is required for an electrical charge to flow through a closed circuit?

A potential difference

What is the flow of electrical charge?

electrical current

What equation links charge flow, current and time?

Charge flow \= Current x Time

What is the standard unit for current?

Amps

What is the standard unit for Charge flow?

Coulombs

What is the standard unit for time?

Seconds

What is the equation that links resistance, potential difference and current?

Potential difference \= Current x Resistance

What two things does the current flowing through a component depend on?

Resistance
Potential Difference

If you increase the resistance of a
component what happens to the current, for a set potential difference

Decreases

What is the standard unit for resistance?

Ohms

What is the standard unit for potential difference?

Volts

How are current and potential difference linked in an ohmic conductor

They are directly proportional

Through which component is resistance constant?

Ohmic conductor

How does the resistance of a filament lamp change as the temperature increases?

It increases

How does the current flow in a diode?

only flows in one direction

What can you tell me about the resistance in a diode?

Very high in the reverse direction

How does the resistance of a thermistor change as the temperature increases?

It decreases

How does the resistance of an LDR change as light intensity increases?

It decreases

What could LDR's be used for

Switching lights on when it gets dark

What could a thermistor be used for?

In a thermostat to control heating

What is the current like in a series circuit?

the same everywhere

What is the total resistance of two
components in a series circuit?

It is the sum of the resistance of each component

What is the total resistance of two resistors connected in parallel?

Less than the resistance of the smallest resistor

What type of supply is the mains electricity in the UK?

AC

What is the frequency of the domestic electricity supply in the UK?

50Hz

What is the voltage of the domestic electricity supply in the UK?

230V

What type of potential difference varies between a positive and negative value?

Alternating

What type of potential difference is only found in the positive?

Direct

How are most electrical appliances
connected to the mains?

Using a three-cord cable

What colour is the live wire?

Brown

What colour is the neutral wire?

Blue

What colour is the earth wire?

Green and yellow stripes

What does the live wire carry?

The alternating potential difference from the supply

What does the neutral wire do in a plug?

Completes the circuit

What does the earth wire do in a plug?

It is a safety wire to stop an appliance becoming live

What is the potential difference between the live wire and the earth?

230V

What is the voltage of the neutral wire

At or close to 0V

What is the voltage of the earth wire

0V, unless there is a fault

What equation links power, potential difference and current?

Power \= Potential difference x Current

What equation links current, resistance and power?

Power \= (Current)2 x Resistance

What does the amount of energy an appliance transfers rely on?

- How long the appliance is switched on for
- The power of the appliance

What is done when charge flows in a circuit?

Work

What equation links energy transferred, power and time?

Energy transferred \= Power x Time

What equation links charge flow, potential difference and energy transferred

Energy transferred \= charge Flow x Potential Difference

What is the National Grid?

A system of cables and transformers linking power stations to consumers

What is transferred from power stations to consumers using the National Grid?

Electrical power

What are used to increase the potential difference from the power station to the transmission cables?

Step-up transformers

What are used to decrease the potential difference for domestic use in the National Grid?

Step- down transformers

What is the potential difference like in the transmission cables in the National Grid?

Very high

What is the equation to work out density?

density\= mass/volume

Standard unit for density?

Kg/m³

When a substance changes state what
happens to the mass?

It stays the same

Why is a physical change different from a
chemical change?

In physical changes the material recovers
its original properties if the change is
reversed

What do we call the energy stored inside a
system by the particles that make up the
system?

Internal energy

What is the internal energy of a system
made up of

The total kinetic and potential energy of
all the particles

What effect does a change of state have on
the overall temperature of a system?

None

What does the increase in temperature of
a material depend on?

- The mass of the substance
- The type of material
- The energy input into the system

What is the energy needed for a substance
to change state called?

Latent heat

What is the amount of energy required to
change the state of one kilogram of a
substance with no change in temperature?

Specific Latent Heat

What can a gas do?

Compressed or expanded

What can a pressure produce?

A net force at right angles to the wall of
the container (or any surface)

What is pressure measured in?

Pascals (Pa)

What is volume measured in?

m^3

What is the equation that links volume,
pressure and constant, for a fixed mass of
gas held at a constant temperature?

pressure × volume \= constant

What is work the transfer of?

Energy by a force

What will work do to a gas?

Increase the internal energy and
temperature

What is the unit for specific latent heat?

J/kg

What is the specific latent heat of fusion?

The change of state from solid to liquid

What is the specific latent heat of
vaporisation?

The change of state from liquid to vapour

How do the particles in a gas move?

randomly

What is the temperature of a gas related
to?

The average kinetic energy of the
molecules