Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Physics > Electricity > Flashcards

Electricity Flashcards

(70 cards)

Start Studying
1
Q

What unit is used to measure current?

A

Amps (A)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the unit of charge?

A

Coulombs (C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What unit is used to measure energy?

A

Joules (J)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What unit is used to measure resistance?

A

Ohms (Ω)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the unit of voltage / potential difference?

A

Volts (V)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What unit is used to measure electrical power?

A

Watts (W)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is Voltage?

A

The energy transferred per unit charge through a component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the relationship between voltage, energy, and charge?

A

V = E/C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the relationship between voltage, current, and resistance?

A

V = I x R

This formula expresses Ohm’s Law in electrical circuits.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does current represent in an electrical context?

A

The rate of flow of electric charge

Current is typically measured in amperes (A).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Do electrons or the current flow positive to negative?

A

Current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the equation for charge?

A

Q = I x t

This equation relates charge (Q) to current (I) and time (t).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens when current flows through a lamp or LED?

A

It lights up, which can help to prove that a current is flowing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why does a current in a resistor result in transfer of energy and an increase in temperature?

A

The flow of electrons causes collisions that convert electrical energy into heat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What device is used to measure current?

A

Ammeter

Ammeters are connected in series to measure current in a circuit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the role of a fuse in an electrical circuit?

A

To protect the circuit from overcurrent

Fuses melt and break the circuit when current exceeds a safe level.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does a thermistor do?

A

Measures temperature

Thermistors change resistance based on temperature variations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does the total current at a junction in a circuit represent?

A

The total current flowing in must equal the total current flowing out of the junction

This is known as Kirchhoff’s Current Law.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the voltage across components connected in parallel?

A

The voltage across each is the same

This means each component experiences the same potential difference.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens to the circuit when one component in a series circuit is removed?

A

The circuit is broken, and everything stops working.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the relationship between current, voltage, and resistance in a circuit?

A

Current depends on voltage and resistance due to V=IR.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens to current if the resistance of the circuit increases?

A

Current decreases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What happens to current if the voltage increases?

A

The current increases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the effect of adding a second resistor in parallel on the total resistance of a circuit?

A

The total resistance of a circuit decreases.

Because there are now alternate routes for the current to flow through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is a practical benefit of parallel circuits?
You can turn only one light on or off, and if one breaks, the others still work.
26
What is the relationship between voltage and current in fixed resistors?
Voltage and current are directly proportional as resistance is constant.
27
What happens to the resistance of a lamp as current increases?
Resistance increases as the bulb heats up.
28
What is a characteristic of a diode?
A diode only lets current flow one way.
29
What happens to current when there is negative voltage in a diode?
No current flows.
30
Why does resistance change in a metal wire as it heats up?
Atoms/ions vibrate faster, leading to more collisions with electrons.
31
How does the length of a wire affect resistance?
Longer wires have more resistance due to more collisions.
32
What does an LDR change based on light?
Its resistance ## Footnote LDR stands for Light Dependent Resistor.
33
How does the resistance of an LDR behave in bright light?
It falls ## Footnote This allows more current to flow.
34
What happens to the resistance of an LDR in darkness?
It is high ## Footnote Less current flows in darkness.
35
What is a thermistor?
A temperature-dependent resistor ## Footnote Thermistors are used for temperature detection.
36
What happens to the resistance of a thermistor in hot conditions?
It drops ## Footnote This allows for better conductivity in higher temperatures.
37
What happens to the resistance of a thermistor in cool conditions?
It increases ## Footnote This reduces current flow in lower temperatures.
38
What are the three wires in a plug?
Live, neutral, earth ## Footnote Each wire has a specific function in electrical safety.
39
What is the purpose of the earth wire?
To prevent electric shocks in emergencies ## Footnote It provides a safe path for excess current.
40
What voltage does the live wire alternate between?
Around + and - 230V
41
What is the voltage of the neutral wire?
Always at 0V ## Footnote This wire completes the circuit back to the source.
42
What happens if the live wire touches a metal case?
A big current flows out the earth wire, due to its low resistance. This melts the fuse so no current can flow anmore.
43
What does a circuit breaker do when it detects a surge in current?
Breaks the whole circuit ## Footnote Circuit breakers can be reset by flipping a switch.
44
True or False: Circuit breakers operate slower than fuses.
False ## Footnote Circuit breakers operate much quicker and are safer.
45
What is double insulation?
A system where the appliance has no exposed metal parts, preventing electric shock due to plastic insulation. ## Footnote Double insulation stops the flow of current, as plastic is an insulator.
46
What is the formula for electrical energy transferred?
Energy transferred = current x voltage x time or Energy transferred = charge x voltage
47
What type of current does a battery or cell use?
Direct current (DC), which flows in the same direction. ## Footnote DC is different from alternating current (AC), which switches direction.
48
How can insulating materials be charged?
By friction, leading to a build-up of static electricity. ## Footnote When insulating materials are rubbed together, one gains a negative charge while the other becomes positively charged.
49
What happens when a cloth duster is rubbed against a polythene rod?
Electrons flow from the cloth to the rod, making the rod negatively charged and the duster positively charged.
50
What happens when a cloth duster is rubbed against an acetate rod?
Electrons flow from the rod to the cloth, making the cloth negatively charged and the rod positively charged.
51
What is the formula for power in electrical circuits?
Power = current x voltage (P = IV).
52
What does the term 'static electricity' refer to?
The accumulation of electric charge on insulating materials. ## Footnote Static electricity occurs when charges do not flow away from the insulator.
53
What is the mains voltage in an alternating current system?
+ 230V and - 230V switching continuously. ## Footnote This indicates the alternating nature of mains electricity.
54
What determines the selection of a fuse for an appliance?
The operating current of the appliance, choosing a fuse that melts a few amps above that. ## Footnote This ensures safety and prevents damage to the appliance.
55
What is a gold-leaf electroscope?
A device with a metal disc connected to a metal rod, at the bottom of which are two thin pieces of gold leaf.
56
What happens when a charged rod is brought close to a gold-leaf electroscope?
Electrons are either attracted to or repelled from the rod, inducing a charge in the disk and gold leaves. Since both will have the same charge, they repel and rise up away from each other
57
What happens to the gold leaves when the charged rod is removed?
They discharge and fall again.
58
How can you test the charge of a rod using suspension?
Suspend a rod with a known charge on a thread and observe attraction or repulsion with the test rod. If there is attraction, it has the opposite charge, if there is repulsion, they have the same charge.
59
What is the main component of a van de Graaff generator?
A rubber belt moving around plastic rollers under a metal dome.
60
How is an electrostatic charge built up in a van de Graaff generator?
Through friction from the moving belt.
61
What effect does the charge from a van de Graaff generator have on the human body?
It causes charges to flow into your body and spread out, making individual hairs repel each other and stand on end.
62
What is a danger of electrostatics when filling fuel?
Friction can build up, leading to a spark and potentially causing a fire.
63
How can earthing wires help prevent electrostatic dangers in fuel tanking?
They connect the fuel tank and pipe, preventing charge build-up.
64
What causes lightning in clouds?
Raindrops or ice bump together, knocking off electrons, creating a positive charge at the top and a negative charge at the bottom. This creates a huge voltage, releasing the energy as a spark
65
How do inkjet printers use electrostatics?
Deflection plates determine the direction of tiny ink droplets, and your printout is made of a lot of tiny dots.
66
What is the process of how a photocopier works?
Friction causes static electricity on a drum (+), and an image is projected onto it. The light bits de-charge, but the dark bits remain +. Powdered Ink (-) sticks to the charged part of the drum and paper (+) is pressed on it so the ink powder sticks to the paper. It is then heated so the ink melts onto it.
67
What charge do all paint droplets that exit the spray paint gun have?
The same charge ## Footnote This charge causes the droplets to repel each other.
68
What happens to paint droplets due to their same charge?
They spread out ## Footnote This occurs because each droplet repels the others.
69
How does the car panel affect the paint drops?
It attracts the paint drops, as it has the opposite charge ## Footnote This leads to a uniform coating on the panel.
70
What is the result of the interaction between the charged paint droplets and the car panel?
The car panel is covered in an even layer of paint ## Footnote This is due to the attraction between opposite charges.

Physics (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions