energy stores, transfers and pathways

Question 1

whats energy and what is it measured in

Answer 1

energy is the ability for something to do work
its measured in joules (j)

Question 2

what is the law of conservation of energy

Answer 2

the law of conservation of energy tells us that energy cannot be created or destroyed, just transferred from one store to another

Question 3

what is an energy store

Answer 3

a way in which a particular type of energy is stored

Question 4

what is an energy pathway

Answer 4

the way energy is transferred from one energy store to another

Question 5

name the eight energy stores

Answer 5

magnetic
thermal
chemical
kinetic
electrostatic
elastic potential
gravitational potential
nuclear

Question 6

what do the eight energy stores mean

Answer 6

kinetic - moving objects
elastic potential - stretched or squashed objects
thermal - energy in warm objects
chemical - stored energy from a fuel
nuclear - radioactive objects
magnetic - magnetic objects
electrostatic - between two charged objects
gravitational potential - objects that have been lifted up

Question 7

give 2 examples for each energy store

Answer 7

magnetic - compasses, fridge magnets
thermal - stove, hot coffee
chemical - foods, muscles
kinetic - bus, meteor
electrostatic - thunderclouds, generators
elastic potential - compressed springs, inflated balloons
gravitational potential - aeroplanes, kites
nuclear - uranium, nuclear reactors

Question 8

how is an energy store transferred from one to another

Answer 8

through/by energy pathways

Question 9

name the four energy pathways and what they mean

Answer 9

heating - if there is a temperature difference then heat will move from a hotter place to a colder place
electrically - carried by moving electrons in an electric current
radiation - transferred via waves (sound waves, light waves, microwaves, sound waves etc)
mechanically - by force being applied from a distance

Question 10

if i were to play with a wind up toy car, what energy stores and pathways would it go through?

Answer 10

kinetic (hand) –> elastic potential (pulling the string) —> kinetic (the car moving)
mechanically x2

Question 10

if i were to drop a ball, what energy stores would increase/decrease

Answer 10

kinetic - increase
gravitational potential - decrease

Question 10

when energy is transferred, what do energy stores do?

Answer 10

increase or decrease

Question 11

what is power

Answer 11

the rate of energy transfer

Question 11

if i were to pull down a spring and release it, what energy stores and pathways would it go through?

Answer 11

kinetic (hand) –> elastic (pulling the spring) –> gravitational (spring at a height) –> kinetic (spring moving up)

Question 12

what is the equation for power and how do you measure it

Answer 12

energy (j)
__________
time (sec)
measures in watts (w)

Question 13

if a microwave generates 300J of energy how much power does it generate in 6 minutes

Answer 13

50 w

Question 14

if a microwave has a power rating of 4000W, how much energy would it transfer in 9 minutes

Answer 14

39000 J

Question 14

if a microwave has a power rating of 2000W and transfers 400000J, how long was it left on for?

Answer 14

200 seconds, aka 2 minutes and 20 seconds

Question 15

what is efficiency?

Answer 15

the proportion of energy transferred into something useful

Question 16

how is efficiency calculated and what is it measured in

Answer 16

Efficiency = useful energy ÷ total energy x 100
it doesnt have a unit because it is dimensionless, so we mostly write it as a percentage

Question 17

what happens to waste/ non useful energy

Answer 17

its turned into heat

Question 18

anomaly

Answer 18

a measurement that doesnt seem to fit the expected pattern

Question 18

if a light bulb has:
input electrical energy of 100J
useful light energy of 10J
wasted heat energy of 90J
what is the efficiency

Answer 18

10%
10/100 x 100 = 10

Question 19

uncertainty

Answer 19

how much your results could be off by

Question 20

reproducible

Answer 20

measurements are similar when repeated by others

Question 20

repeatable

Answer 20

measurements are similar if you did the same experiments the same way

Question 21

draw a cell (battery) wire light bulb ammeter voltmeter switch (open and closed) resistor

Answer 21

check the sheet of paper zjvh

Question 21

what does a series circuit look like

Answer 21

__________________battery_______________ | | | | | | | | | | | | | | _________________________________________ all components in 1 loop

Question 22

precision

Answer 22

how close your measurements are to each other

Question 22

accuracy

Answer 22

how close your result is to the expected value

Question 23

what does a parallel circuit look like

Answer 23

im too lazy check the sheet two or more loops/paths for the current to take

Question 24

what is current

Answer 24

current is the rate of flow of charge in a circuit

Question 25

im an idiot, explain current

Answer 25

in a circuit there are electrons that are free to move around the circuit - this flow of charge is basically electricity the faster these charged electrons can flow round the circuit, the higher the current is

Question 26

what, how and where is current measured in

Answer 26

amps (a), using an ammeter in a series circuit

Question 27

whats potential difference

Answer 27

pt reflects the energy transferred by the charges as they move between two points in dum dum words, a measure of energy, transferred between two points in a circuit

Question 28

how does energy transferred affect pt

Answer 28

the more energy transferred by the charges, the higher the potential difference is

Question 29

what, how and where is pt measured

Answer 29

in volts (v) using a voltmeter in a parallel circuit

Question 29

tell me about current and pt in a series circuit and what happens when you add more components

Answer 29

in a series circuit, current values stay the same. by adding components, the current decreases because of the flow of electrons are slower and theres more resistance in a series circuit, the values across the components add up to the total pt

Question 30

tell me about current and pt in a parallel circuit and what happens when you add more branches

Answer 30

in a parallel circuit, the currents in the branches adds up to the total current. adding a branch increases the total current. in a parallel circuit, pt valuues are the same everywhere.

Question 31

if we had three bulbs in a parallel circuit and a series circuit, which one would be brighter and why

Answer 31

the parallel ones because the current is the same all throughout.

Question 32

if i were to unscrew one out of three bulbs in a series and a parallel circuit, what would happen

Answer 32

parallel - remaining ones stay on series - all go off

Question 33

why are series circuits dimmer if we add more bulbs

Answer 33

theres more components

Question 34

what are the disadvantages of a parallel circuit

Answer 34

battery goes down faster cos of brightness

Question 35

how do you calculate ELECTRICAL power and what is it measured in

Answer 35

current x potential difference watts (w)

Question 36

how do you calculate nrg at home add all measurements

Answer 36

power (kW) x time (hour) = electrical energy (kWh)

Question 36

how do you calculate the cost of nrg at home

Answer 36

no. of units x cost of 1 unit answer in pence

Question 36

give me the units + cost if 1 unit of electricity costs 12p a 2kW heater used for 10 hours a 300w hairdryer used for 30 mins

Answer 36

units: 20 kWh cost: 240p units: 0.15 kWh cost: 1.8p

Question 37

name 5 ways we can reduce the amount of energy we use and produce

Answer 37

buy an electric car install solar panels start walking or biking spend less time in the shower be mindful of the use of hot water