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Electricity Flashcards

(54 cards)

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1
Q

What is current?

A

A measure of the flow of electrons around a circuit

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2
Q

What is the unit of Electric Current?

A

Amperes, amps, or ‘A’

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3
Q

What is Potential Difference?

A

The force driving the flow of electrons around a circuit

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4
Q

What is Resistance?

A

Everything that resists or opposes the flow of electrons in a circuit

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5
Q

What Are The Units Of Potential Difference?

A

Voltage, volts, and ‘V’

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6
Q

What is the unit of Resistance?

A

Ohms (Ω)

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7
Q

What is the symbol for a filament lamp?

A

A circle with a cross inside

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8
Q

What is the direction of current flow?

A
  • Electrons flow - Negative → Positive
  • Conventional current - Positive → Negative
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9
Q

What are the circuit symbols for a cell

A

A cell is one long line (positive) and one short line (negative)

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10
Q

What are the circuit symbols for a battery?

A

Two or more cells joined together

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11
Q

What is the definition of charge (Q)?

A

The measure of the total current that flows within a certain period of time

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12
Q

What is the unit for charge?

A

Coulombs (C)

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13
Q

What is the equation for charge (Q)?

A

Q=I×t
Where:
Q = Charge (C)
I = Current (A)
t = Time (s)

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14
Q

What is a series circuit?

A

A circuit with only a single loop, where components are connected one after another

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15
Q

What happens if a component in a series circuit is disconnected?

A

The whole circuit stops working

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16
Q

How is voltage shared in a series circuit?

A

The total voltage of the battery is shared across all components

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17
Q

How is voltage across a single component calculated?

A

V=I×R

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18
Q

What is the function of a voltmeter?

A
  • Measures the potential difference across a component
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19
Q

What happens to components with higher resistance in a series circuit?

A

Components with higher resistance get a larger share of the total voltage

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20
Q

What is a parallel circuit?

A

A circuit with more than one loop, where each loop typically contains only one component

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21
Q

What happens if one component in a parallel circuit breaks?

A

The overall circuit remains intact, and other components continue working

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22
Q

How is voltage shared in a parallel circuit?

Study These Flashcards
A

shared equally across all branches of the circuit

23
Q

How is current shared in a parallel circuit?

Study These Flashcards
A
  • The total current splits between the loops
  • The sum of the currents in all loops equals the total current of the circuit
24
Q

How does resistance affect current in a parallel circuit?

Study These Flashcards
A

Adding more resistors decreases the total resistance, increasing the total current.

25
What happens to the total resistance when more components are added in parallel?
The total resistance of the circuit decreases
26
What is the relationship between total resistance and loops in parallel?
The more loops added, the lower the total resistance of the circuit
27
Why are parallel circuits more practical than series circuits?
In parallel circuits, if one component breaks, the rest of the circuit still works
28
What are the 3 formulas for energy?
Energy (E) = Power (P) x Time (t) Energy (E) = Voltage (V) x Current (I) x Time (t) Energy (E) = Charge (Q) x Voltage (V)
29
What are the key characteristics of the mains supply in the UK?
The mains supply is an alternating current (AC) of 230 volts and 50 hertz
30
What are the three wires in a three-core cable?
- Live wire (Brown) - Neutral wire (Blue) - Earth wire (Green & Yellow)
31
What is the function of the live wire, and what is its potential difference?
- Provides the alternating potential difference from the mains supply - P.D: 230V
32
What is the function of the neutral wire, and what is its potential difference?
- Completes the circuit by carrying away current - P.D: 0 Volts
33
What is the function of the earth wire, and what is its potential difference?
- Stops the appliance casing from becoming live - P.D: 0 Volts
34
What happens if the live wire touches the casing of an appliance?
Provides a safe pathway for current, preventing electric shocks
35
Why is touching the live wire dangerous?
Has a potential difference of 230 volts, and since humans have a potential difference of 0 volts, a large current will flow through the body, causing a shock
36
How does electricity flow in a circuit with a three-core cable?
- Flows into the device through the live wire - Flows out through the neutral wire
37
Why should you never touch a plug socket, even if it’s switched off?
The live wire still has a potential difference, so contact could result in an electric shock
38
What are the wires inside a three-core cable made of, and why?
The wires are made of copper because it conducts electricity well
39
Why are wires coated with plastic?
The plastic acts as an insulator for safety
40
What are surges in an electrical circuit?
Sudden increases in current
41
Why do surges happen?
- Circuit changes - Due to faults in the circuit or appliance
42
What can electrical surges cause?
- Damage appliances - Cause fires - Result in electric shocks
43
What is the function of a fuse in a circuit?
Breaks the circuit by melting when the current becomes too high, preventing further current flow
44
How do you select a fuse rating for an appliance?
Choose a fuse a few amps higher than the appliance’s normal operating current
45
What are the advantages of fuses?
- Simple - Cheap
46
What are the Disadvantages of fuses?
Permanently damaged after a surge and need replacing
47
How do circuit breakers differ from fuses?
Circuit breakers trip when the current is too high but can be reset instead of replaced
48
What is the role of the earth wire?
Provides an alternative pathway for current to flow away, preventing electric shocks
49
What is double insulation?
Double insulation covers appliances with plastic casing
50
Why is double insulation is useful?
So there are no exposed metal parts, preventing electric shocks
51
What wires are found in appliances with double insulation?
- Live wires - Neutral wires
52
What happens if a live wire touches an appliance's casing?
Make the casing live, and touching it could result in a severe electric shock
53
What are the benefits of circuit breakers over fuses?
- Circuit breakers - can be reset after a surge - Fuses - must be replaced
54
How are fuses and circuit breakers similar?
Both break the circuit when the current gets too high, preventing damage and electric shocks

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