Electricity Flashcards

1
Q

what is electrical current?

A

current is the flow of electrical charge

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2
Q

how does the rate of flow of charge relate to current?

A

the greater the rate of flow of charge, the greater the current

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3
Q

What does it mean that the current has the same value at any point in a single closed loop?

A

it means that the current is constant throughout the circuit

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4
Q

what is the behavior of current through a diode?

A

the current flows in one direction only, with higher resistance in the reverse direction

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5
Q

how does current change with increasing current in a resistor

A

as current increases, electrons gain more energy and collide with atoms, increasing resistance.

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6
Q

how does temperature affect the resistance of a thermistor?

A

the resistance of a thermistor decreases at higher temperatures.

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7
Q

how does the length of a wire affect its resistance?

A

the greater the length of the wire, the more resistance it has.

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8
Q

What is the behavior of an LDR in different light conditions?

A

the resistance of an LDR decreases with greater light intensity and is highest in darkness

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9
Q

what is the function of a diode in a circuit?

A

a diode allows current to flow freely in one direction and has high resistance in the opposite direction

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10
Q

what is the total resistance in a series circuit?

A

the total resistance is the sum of the resistances of each component

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11
Q

how does current behave in a parallel circuit?

A

the total current into a junction equals the total current in each of the branches

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12
Q

what is the frequency and voltage of mains electricity in the UK?

A

the frequency is 50 Hz and the voltage is about 230 V

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13
Q

What is the difference between AC and DC current?

A

AC is alternating current that varies continuously, while DC is direct current that flows in one direction only

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14
Q

What are the three wires in a plug and their functions?

A

Live wire (brown, 230V), neutral wire (blue, 0V), and earth wire (green/yellow, 0V)

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15
Q

what is the purpose of the earth wire in a plug?

A

The earth wire is a safety wire that prevents the appliance from becoming live in case of a fault.

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16
Q

What is the formula for energy transferred in terms of power and time?

A

E = P x t

17
Q

What is the national grid?

A

The national grid is a system of cables and transformers linking power stations to consumers across the UK

18
Q

what is the function of transformers in the national grid?

A

Transformers change the potential difference for efficient power transfer

19
Q

What do step-up transformers do?

A

Step-up transformers increase the potential difference from the power station to the National Grid

20
Q

what do step-down transformers do?

A

Step-down transformers decrease the potential difference from the national grid to consumers for safety

21
Q

what is the behavior of like and opposite charges?

A

Like charges repel each other, while opposite charges attract each other

22
Q

What is the difference between insulators and conductors?

A

Insulators do not conduct electricity as the electrons are fixed, but conductors can carry electricity as their electrons are delocalized

23
Q

What causes sparking in static electricity?


A

Sparking occurs when enough charge builds up and jumps through the air to balance out the charges.

24
Q

How does the strength of the electrostatic force change with charge and distance?


A

The greater the charge, the greater the force, and the closer the objects are, the greater the force felt.

25
Q

What are the key differences between series and parallel circuits?


A

Series Circuits:
Current follows a single path.
Current is the same everywhere.
Total resistance is the sum of individual resistances.
Potential difference is shared across components.

Parallel Circuits:
Current splits into multiple paths.
Total current into a junction equals the total current in each branch.
Potential difference is the same across each branch.
Total resistance is less than the smallest resistor.

26
Q

What are the characteristics of static electricity?


A

Charge is transferred when insulators are rubbed together.
Conductors remain neutral as electrons can flow.
Sparking occurs when charge builds up and jumps to balance charges.