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Physics Gcse Higher 9-1 > Energy and electricity > Flashcards

Flashcards in Energy and electricity Deck (63):
1

What are the 8 energy stores?

Thermal Kinetic gravitational potential elastic potential chemical magnetic electrostatic nuclear

2

Give two methods of energy transfer

Mechanically and electrically

3

How does the way energy is stored change when someone throws a ball upwards?

Energy transferred from the chemical energy store the persons arm to the kinetic energy stores of the arm and the ball once the ball with release energy is transferred from kinetic energy store the board to its gravitational potential gravity energy store

4

Which has more energy in its kinetic energy store a person walking at 3 mph or a lorry travelling at 60 mph

I Lorry travelling at 60 mph

5

What is specific heat capacity

Specific heat capacity of the amount of energy needed to raise the temperature of 1 kg of the substance by 1°C

6

What is the conservation of energy principle

Energy can be transferred usefully stored or dissipated but can never be created or destroyed

7

What is conduction

Conduction is the process where vibrating particles transfer energy to neighbouring particles

8

What is convection

Convection is where energetic particles move away from the hotter to cooler regions

9

What is Power stage units is measured in

Power is the rate of doing work the units are watts

10

Give one where you could use the frictional forces in the hinge of an automatic door

Lubrication

11

For a given material how does it thermal conductivity affect the rate of energy transfer through it

The higher the rate of thermoconductivity the greater the rate of energy transfer through it

12

Why is the efficiency of an appliance always less than 100%

Some of the energy is always dissipated so less than 100% of the input energy transfer transferred usefully

13

Name three nonrenewable energy sources

Coal oil and natural gas

14

Give one advantage and one disadvantage associated with the reliability of renewable resources

Will never run out and energy output often can’t respond to immediate increases of energy demand

15

Give two ways in which student cold and energy resource can cause environmental problems

It releases greenhouse gases and contributes to global warming causes acid rain

16

Suggest two reasons why we can’t just stop using fossil fuels immediately

Renewable resaws is don’t currently provide enough energy and energy from honourable resources cannot be relied on upon currently

17

What are the units for resistance

Ohms

18

How does the current through a component vary with resistance for a fixed potential difference

The greater the resistance of the smaller the current Small of the resistance the greater the current

19

Give an example of an Ohmic conductor

A wire/ resistor

20

How should a voltmeter be connected in a circuit to measure the potential difference across the component

Across

21

What is an I-V characteristic

A graph that shows how the current flowing through a component change it as potential difference across it varies

22

One use of a light dependent resistor

Automatic night lights/ burglar detector

23

What happened to the resistance of a thermistor as the temperature increases

The resistance decreases

24

Give. One practical disadvantage of series circuits

You can’t switch components on and off independently

25

How do you work out the total resistance in a series circuit

Total resistance of the sum of all resistances

26

Which has the higher total resistance to resistors in a series all the same to resistors in parallel

Two resistors connected in series

27

Name the three wires in a three core cable that connects electrical appliances to the mains supply

Livewire neutral wire and earth wire

28

What is the main energy transfer one electric current flows through an electric kettle

Energy is transferred electronically to the thermal energy store of the heating element

29

What is the National Grid

Network of cables and Transformers that distributes electricity across the country

30

Define current

Flow of charge

31

What is meant by potential difference and resistance in the circuit

Potential difference is the driving force that pushes the charge around and resistance is anything in a circuit that slows the flow down

32

What is an Ohmic conductor

It obeys ohms law and has a constant resistance at a constant temperature and current flowing through the conductor is directly proportional to the potential difference across it

33

Name one linear component and one non-linear components

A resistor is linear and a diodes is non-linear

34

Explain how the resistance of an LDR varies with light intensity

As it gets darker resistance increases as it gets lighter resistance decreases

35

What happens to the resistance of a thermistor as it gets colder

As it gets colder resistance increases

36

True or false potential difference is shared between components in a series circuit

True

37

True or false the potential difference across each component connected in a parallel is different

False

38

Explain why adding resistors in parallel decreases the total resistance of the circuit but adding them on a series increase of the total resistance

Potential difference is the same everywhere is a parallel circuit which means the current flow is the same as the potential difference for every resistor you add but by adding another loop current has more directions to go in which increases current and decreases resistance. However in series the PD across each resistor is lower so the current through each resistor is also lower and current is the same everywhere so current is reduced when a resistor is added this means total resistance increases

39

True or false? Mains supply electricity is an alternating current

True

40

What is the potential difference and the frequency of the uk mains supply

230V and 50Hz

41

Name and give the colours of the three wires in a three core cable

Live-brown
Neutral-blue
Earth-yellow and green

42

Explain why touching a live wire is dangerous

You would get an electric shock which means current will flow through you

43

What is the power rating of an appliance

Shows the power it consumes

44

Explain why electricity is transferred by the national grid at high PD but low current

Less waste energy

45

What are the functions of a step up and a step down transformers

Potential difference is increased using a step up transformer for high demand and reduced by step down transformers

46

What is a system

A single object

47

Describe the energy transfers that occur when a car collided with a stationary object

The object does the work as it causes energy to be transferred from the car’s kinetic energy store to other energy stores

48

If energy is transferred to an object’s kinetic energy store what happens to the speed

Slows down

49

What kind of energy store is energy transferred to when you compress a string

Elastic potential energy

50

Which does he variable ‘e’ stand for in the equation for energy in elastic potential energy store

Elastic potential energy

51

What is the definition of the specific heat capacity of a material

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

52

Suggest why a material with a high specific heat capacity is better suited for use in a heating system than a material with a low specific heat capacity

It absorbs heat and raises heat quicker

53

True or false? Energy can be destroyed

False

54

How much energy is transferred per second to a 50W device

50J

55

True or false? A high thermal conductivity means there is a high rate of energy transfer

True

56

How can you reduce unwanted energy transfers in a machine with moving components

Insulating or lubricating

57

Give four ways to prevent unwanted energy transfers in the home

Loft insulation cavity walls double glazed windows and draught excluders

58

True or false thicker walls cool down a house quicker

False because thicker walls lower the rate of thermal conductivity and therefore the rate of energy transfer

59

Name four renewable energy resources

Wind,hydro,solar and nuclear

60

What’s the difference between renewable and non renewable

Renewable has a constant supply and non renewable cannot be made again

61

Give an example of how a renewable energy resource is used in every day life

Electricity in houses supplies by gas and oil

62

Explain why solar power is considered to be a fairly reliable energy resource

It’s a reliable source but only during day time

63

Give one environmental impact of using wave power to generate electricity

Causes flooding and loss of habitat