energy

Question 1

can you name the different forms of energy

Answer 1

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

Question 2

can energy be created

Answer 2

NO - energy is transformed from one form to another

Question 3

can energy be destroyed

Answer 3

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

Question 4

what kind of energy is changed into electrical energy by a generator

Answer 4

the generator uses kinetic(movement) energy to make electrical energy

Question 5

what sort of energy does a ball have if it is on the top of a wall and then falls to the ground

Answer 5

on top of the wall it has gravitational potential energy which is transformed into kinetic energy as it falls

Question 6

a TV uses electrical energy - what does it transform it into

Answer 6

electrical energy is transformed into light energy (pictures), sound energy and heat energy

Question 7

which type of energy is wasted in a TV Light energy (pictures), sound energy or heat energy

Answer 7

Heat energy - we don’t use a TV to get warm

Question 8

in a car name the forms of useful energy

Answer 8

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

Question 9

in a car name the forms of wasted energy

Answer 9

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.

Question 10

energy is measured in Joules. true or false

Answer 10

true - a joule is the amount of energy it takes to lift a 1m weight 1m

Question 11

what does a SANKEY diagram show

Answer 11

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

Question 12

what do we mean by ‘conservation of energy’

Answer 12

energy cannot be created or destroyed

Question 13

what does the term useful energy mean

Answer 13

the energy that is used for the right form eg light bulb producing light energy

Question 14

what do we mean by the term wasted energy

Answer 14

wasted energy is the energy that is not transferred to the chosen use eg heat energy produced by a light bulb

Question 15

what happens to wasted energy

Answer 15

it spreads out into the surroundings

Question 16

what is the useful and wasted energy from a radio

Answer 16

useful - sound energywasted - heat energy

Question 17

the light given off by a fire is wasted true or false

Answer 17

we use a fire for heat so light energy is wasted

Question 18

name the types of energy that are transferred from the electrical energy going into a TV

Answer 18

Useful energy - light (pictures) and sound energywasted energy - heat energy

Question 19

what do we mean by the term ‘efficiency’

Answer 19

when we talk about a machine being efficient we mean that more of the energy it takes in is transformed into useful energy

Question 20

efficiency = useful energy transferred by a device ? the total energy supplied to the devicewhich answer fits in the equationDIVIDED BY OR MULTIPLIED BY

Answer 20

efficiency = useful energy transferred by a device DIVIDED BY the total energy supplied to the device

Question 21

efficiency is always a percentagetrue or false

Answer 21

true because it is always less than the total energy that the device is supplied

Question 22

what unit do we measure the power of a device is measured in watts or kilowattstrue or false

Answer 22

TRUE

Question 23

power (in watts) = energy transferred ( in Joules) divided by the time taken (in minutes)true or false

Answer 23

False power (in watts) = energy transferred ( in Joules) divided by the time taken (in SECONDS)

Question 24

the energy supplied to a device is called kilojouletrue or false

Answer 24

false its measured in kilowatts (kW)

Question 25

electricity used is measured in

Answer 25

units

Question 26

cost of electricty is

Answer 26

number of units used MULTIPLIED by the cost per unit