P2 Electricity

Question 1

Draw the circuit symbol for a cell

Answer 1

Question 2

Draw the circuit symbol for a battery

Answer 2

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Question 3

Draw the circuit symbol for a diode

Answer 3

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Question 4

Draw the circuit symbol for a resistor

Answer 4

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Question 5

Draw the circuit symbol for a variable resistor

Answer 5

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Question 6

Draw the circuit symbol for an LED

Answer 6

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Question 7

Draw the circuit symbol for a lamp

Answer 7

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Question 8

Draw the circuit symbol for a fuse

Answer 8

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Question 9

Draw the circuit symbol for a voltmeter

Answer 9

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Question 10

Draw the circuit symbol for an ammeter

Answer 10

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Question 11

Draw the circuit symbol for a thermistor

Answer 11

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Question 12

Draw the circuit symbol for an LDR

Answer 12

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Question 13

State the rule for current in a series circuit

Answer 13

the current is the same at every point in the circuit and in every component

Question 14

State the rule for potential difference in a series circuit

Answer 14

the total potential difference of the power supply is shared between components

Question 15

State the rule for resistance in a series circuit

Answer 15

the more resistors, the greater the resistance. R_T=R₁+R₂

Question 16

State the rule for current in a parallel circuit

Answer 16

the total current through the whole circuit is the sum of the currents through the separate components

Question 17

State the rule for potential difference in a parallel circuit

Answer 17

the potential difference across each branch in the circuit is the same

Question 18

State the rule for resistance in a parallel circuit

Answer 18

adding more resistors in parallel decreases resistance

Question 19

What colour is the live wire in a three core cable?

Answer 19

brown

Question 20

What colour is the neutral wire in a three core cable?

Answer 20

blue

Question 21

What colour is the earth wire in a three core cable?

Answer 21

green and yellow

Question 22

The brown wire in a plug is the _______

Answer 22

live

Question 23

The blue wire in a plug is the ________

Answer 23

neutral

Question 24

The green and yellow wire in a plug is the ________

Answer 24

earth

Question 25

The potential difference between the live wire and others in the plug is _____ V

Answer 25

230V

Question 26

Current flows into an appliance through the _______ wire

Answer 26

live

Question 27

Current flows out of an appliance through the ______ wire

Answer 27

neutral

Question 28

The _________ wire is a safety feature of appliances

Answer 28

earth

Question 29

Potential difference between the neutral wires and others in the plug should be ____ V

Answer 29

0V

Question 30

Electric Current is….?

Answer 30

the flow of electric charge

Question 31

Potential difference between two points in a circuit is….?

Answer 31

the work done when a couloumb of charge passes between the points.

Question 32

In a circuit the potential difference causes …..?

Answer 32

charge to flow

Question 33

Resistance is…?

Answer 33

caused by anything which opposes the flow of electric charge

Question 34

Particles which can be 'charges' in electric circuits are…

Answer 34

electrons or ions

Question 35

What is a series circuit?

Answer 35

A circuit with only one route for charge to flow

Question 36

What is a parallel circuit?

Answer 36

A circuit with more than one route for charge to flow

Question 37

State the equation which links charge flow, current and time

Answer 37

Q=It

Question 38

State the equation which links current, potential difference and resistance

Answer 38

V=IR

Question 39

State the equation which links current, potential difference and power

Answer 39

P=IV

Question 40

State the equation which links current, power and resistance

Answer 40

P=I²R

Question 41

State the equation which links energy transferred, power and time

Answer 41

E=Pt

Question 42

State the equation which links charge flow, energy transferred and potential difference

Answer 42

E=QV

Question 43

What is the unit of charge flow?

Answer 43

Coulomb ( C )

Question 44

What is the unit of current?

Answer 44

Amps (A)

Question 45

What is the unit for potential difference?

Answer 45

Volts (V)

Question 46

What is the unit for resistance?

Answer 46

Ohms (Ω)

Question 47

What is the unit for power?

Answer 47

Watts (W)

Question 48

Describe the I-V characteristic for a fixed resistor

Answer 48

Current and potential difference are directly proportional, resistance is constant

Question 49

Describe the I-V characteristic of a filament lamp

Answer 49

Resistance is not constant, it increases as p.d. increases

Question 50

Explain why resistance increases with increased p.d. in a filament lamp

Answer 50

temperature increases causing ions to vibrate and increasing collisions with electrons flowing through the filament

Question 51

Describe the I-V characteristic of a diode

Answer 51

The current only flows through the diode in one direction, there is a very high resistance in the reverse direction.

Question 52

Current which regularly changes direction is called…

Answer 52

alternating current

Question 53

An example of alternating current is…?

Answer 53

mains electricity

Question 54

Current which flows in one direction is…?

Answer 54

direct current

Question 55

An example of direct current is…

Answer 55

batteries

Question 56

What is the potential difference of mains electricity in the UK?

Answer 56

230V

Question 57

What is the frequency of the alternating current in UK mains electricity?

Answer 57

50Hz

Question 58

The national grid consists of…?

Answer 58

Cables and transformers

Question 59

Are power stations par of the national grid?

Answer 59

no

Question 60

What does a step up transforIncreases p.d.mer do?

Answer 60

Increases p.d.

Question 61

What does a step down transformer do?

Answer 61

reduces p.d. to 230 V

Question 62

Why are transformers used?

Answer 62

reduce current so that less heat is lost in cables, increases efficiency