Electricity Flashcards

1
Q

What is the value of mains voltage (in the UK)?

A

Mains voltage is 230V.

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2
Q

Describe what would happen to a positive charge if it was placed in the field shown.

A

A positive charge would accelerate towards the negative plate.

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3
Q

What is the name of this component?

A

Loudspeaker

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4
Q

What is the name of this component?

A

npn transistor

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5
Q

How could the air-conditioning circuit (shown) be changed so that it switches on at a different temperature?

A

To switch the circuit on at a different temperature, the variable resistor could be adjusted.

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6
Q

Which quantity is represented by the symbol Q?

A

Q = charge

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7
Q

What is the name of this component?

A

Motor

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8
Q

What is the name of this component?

A

L.E.D. (light-emitting diode)

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9
Q

What is the name of this component?

A

Capacitor

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10
Q

What unit is energy measured in?

A

Energy is measured in joules (J).

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11
Q

Round off this number to 3 significant figures.

1,526.33

A

1,526.33 rounded off to 3 significant figures is

1,530

(the ‘2’ has been rounded up to 3)

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12
Q

How many pencils are there?

A
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13
Q

What unit is voltage measured in?

A

Voltage is measured in volts (V).

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14
Q

What does the prefix k stand for?

A

k stands for kilo

kilo = x 103

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15
Q

What unit is charge measured in?

A

Charge is measured in coulombs (C).

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16
Q

What effect does an electric field have on a charge?

A

An electric field causes a charge to accelerate (due to applying an unbalanced force)

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17
Q

What is the definition of the term power?

A

Power is defined as the amount of energy used per second.

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18
Q

What is the definition of current?

A

Current is how much electrical charge flows (past a point) in one second.

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19
Q

What unit is power measured in?

A

Power is measured in watts (W).

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20
Q

Which quantity is represented by the symbol P, in the equation shown?

A

P = power

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21
Q

Describe how to use an ammeter to measure the current in a component.

A

An ammeter must be connected in series with a component.

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22
Q

Which quantity is represented by the symbol R?

A

R = resistance

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23
Q

Round off this number to 3 significant figures.

6.22789

A

6.22789 rounded off to 3 significant figures is

6.23

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24
Q

How could the resistance of a component be found from this graph?

A

The resistance could be found by

(a) calculating the gradient of the graph
(b) choosing a point on the graph and calculating voltage / current

25
Q

What is the name of this component?

A

Fuse

26
Q

What does d.c. stand for and what does it mean?

A

d.c. stands for direct current, which means the electrons flow in one direction only (negative to positive).

27
Q

What is the name of this component?

A

Variable resistor

28
Q

What is the name of this component?

A

Resistor

29
Q

What is the name of this component?

A

Lamp

30
Q

Round off this number to 3 significant figures.

3.14159

A

3.14159 rounded off to 3 significant figures is

3.14

31
Q

What does a.c. stand for, and what does it mean?

A

a.c. stands for alternating current, which means the electrons change direction every fraction of a second.

32
Q

How could the air-conditioning circuit (shown) be changed so that it performs the opposite job?

A

The circuit can be changed to perform the opposite job by swapping the thermistor with the variable resistor.

33
Q

What does the prefix G stand for?

A

G stands for giga

giga = x 109

34
Q

Will the L.E.D. in this circuit switch on?

Explain your answer.

A

No - the L.E.D. will not switch on.

The positive terminal of the L.E.D. is not connected to the positive terminal of the battery.

35
Q

Which quantity is represented by the symbol V, in the equation shown ?

A

voltage

(or potential difference)

36
Q

Round off this number to 3 significant figures.

0.0025668

A

0.0025668 rounded off to 3 significant figures is

0.00257

37
Q

What does the prefix m stand for?

A

m stands for milli

milli = x 10-3

38
Q

What is the name of this component?

A

MOSFET (transistor)

39
Q

What is the name of this component?

A

Diode

40
Q

What is the name of this component?

A

L.D.R. (light-dependent resistor)

41
Q

Which quantity is represented by the symbol I?

A

I = current

42
Q

What does the prefix M stand for?

A

M stands for mega

mega = x 106

43
Q

What unit is time measured in?

A

Time is measured in seconds (s).

44
Q

Describe how to use a voltmeter to measure the voltage across a component.

A

A voltmeter must be connected in parallel with a component.

45
Q

What does the prefix µ stand for?

A

µ stands for micro

micro = x 10-6

46
Q

Why does an L.E.D. always have a resistor connected in series with it?

A

An L.E.D. always has a resistor connected in series with it to protect the L.E.D.

The resistor will limit the current in the L.E.D.

47
Q

Which quantity is represented by the symbol t?

A

t = time

48
Q

A hairdryer has an operating current of 6.5 amperes.

What value of fuse should be used in the plug of the hairdryer?

A

The fuse rating has to be higher than the operating current.

If the current is 6.5A, a 13A fuse should be used.

49
Q

What unit is current measured in?

A

Current is measured in amperes (A).

50
Q

In the diagram shown, what type of charge does the particle have?

Explain your answer.

A

The particle has a negative charge.

The particle is negative because it is attracted to the positive plate.

51
Q

Describe what would happen to a negative charge if it was placed in the field shown.

A

A negative charge would accelerate towards the positive plate.

52
Q

What does the prefix n stand for?

A

n stands for nano

nano = x 10-9

53
Q

What unit is resistance measured in?

A

Resistance is measured in ohms.

54
Q

What is the name of this component?

A

Cell

55
Q

What is the name of this component?

A

Battery

56
Q

The voltage of a supply is a measure of the ………………. given to the charges in a circuit.

A

The voltage of a supply is a measure of the ENERGY given to the charges in a circuit.

57
Q

Will the L.E.D. in this circuit switch on?

Explain your answer.

A

Yes - the L.E.D. will switch on.

The positive terminal of the L.E.D. is connected to the positive terminal of the battery.

58
Q

What is the purpose of a transistor?

A

A transistor acts as an electronic switch.

(it switches on above a certain voltage)

59
Q

How many types of electric charge are there, and what are their names?

A

There are two types of electric charge - positive and negative