energy Flashcards
can you name the different forms of energy
chemical energy -eg food, coal, oil and gaskinetic energy - energy of movementgravitational potential energy - energy from being high upelastic energy - the energy in a spring or elastic bandelectrical energy - electrical currentthermal (heat) energy - eg from a fire, cooker or the sunlight energy sound energymagnetic - Energy in magnets and electromagnetsnuclear - stored in atoms
can energy be created
NO - energy is transformed from one form to another
can energy be destroyed
no - energy can not be destroyed BUT energy can be lost to the atmosphere eg the heat energy produced by a TV is lost to the atmosphere
what kind of energy is changed into electrical energy by a generator
the generator uses kinetic(movement) energy to make electrical energy
what sort of energy does a ball have if it is on the top of a wall and then falls to the ground
on top of the wall it has gravitational potential energy which is transformed into kinetic energy as it falls
a TV uses electrical energy - what does it transform it into
electrical energy is transformed into light energy (pictures), sound energy and heat energy
which type of energy is wasted in a TV Light energy (pictures), sound energy or heat energy
Heat energy - we don’t use a TV to get warm
in a car name the forms of useful energy
petrol - chemical energylight energy - so we can see where we are going at nightsound energy - so we can listen to musicheat energy - to keep us warmkinetic energy - to make the car move
in a car name the forms of wasted energy
heat energy - the moving parts in the engine release heat into the atmospherenoise energy - the movement in the engine causes noises which are lost to the atmospherekinetic energy - when the engine is moving but the car isn’t the energy is lost as sound and heat energy.
energy is measured in Joules. true or false
true - a joule is the amount of energy it takes to lift a 1m weight 1m
what does a SANKEY diagram show
the amount of energy input and how the energy is outputfor example a T 100J of energy goes into a TV. 48J is transformed into light energy, 37J is transformed into sound energy and 15J is wasted as heat100-(48+37) = 15J wasted
what do we mean by ‘conservation of energy’
energy cannot be created or destroyed
what does the term useful energy mean
the energy that is used for the right form eg light bulb producing light energy
what do we mean by the term wasted energy
wasted energy is the energy that is not transferred to the chosen use eg heat energy produced by a light bulb
what happens to wasted energy
it spreads out into the surroundings
what is the useful and wasted energy from a radio
useful - sound energywasted - heat energy
the light given off by a fire is wasted true or false
we use a fire for heat so light energy is wasted
name the types of energy that are transferred from the electrical energy going into a TV
Useful energy - light (pictures) and sound energywasted energy - heat energy
what do we mean by the term ‘efficiency’
when we talk about a machine being efficient we mean that more of the energy it takes in is transformed into useful energy
efficiency = useful energy transferred by a device ? the total energy supplied to the devicewhich answer fits in the equationDIVIDED BY OR MULTIPLIED BY
efficiency = useful energy transferred by a device DIVIDED BY the total energy supplied to the device
efficiency is always a percentagetrue or false
true because it is always less than the total energy that the device is supplied
what unit do we measure the power of a device is measured in watts or kilowattstrue or false
TRUE
power (in watts) = energy transferred ( in Joules) divided by the time taken (in minutes)true or false
False power (in watts) = energy transferred ( in Joules) divided by the time taken (in SECONDS)
the energy supplied to a device is called kilojouletrue or false
false its measured in kilowatts (kW)
