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physics > electricity > Flashcards

electricity Flashcards

resistors, current, resistance, potenial difference and electrial charge

1
Q

Q: What is current in physics?

A

A: Current is the flow of charge, typically electrons, through a conductor.

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2
Q

Q: How does current flow in a series circuit?

A

A: In a series circuit, the current is the same at all points and flows from positive to negative.

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3
Q

Q: What is the formula relating charge, current, and time?

A

Q=I×t
Where:

𝑄
Q is the charge in coulombs (C),
𝐼
I is the current in amperes (A),
𝑡
t is the time in seconds (s).

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4
Q

Q: What does potential difference (voltage) measure?

A

A: Potential difference measures the difference in energy carried by the current between two points in a circuit.

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5
Q

Q: What is the formula for potential difference (voltage)?

A

A: The formula is V = E/Q, where V is potential difference (voltage), E is energy transferred, and Q is charge.

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6
Q

Q: What is resistance?

A

A: Resistance is how easy or difficult it is for current to flow through a component, measured in ohms.

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7
Q

Q: What is the formula for resistance?

A

R=V/I
Where:

𝑅
R is the resistance in ohms (
Ω
Ω),
𝑉
V is the voltage (or potential difference) in volts (V),
𝐼
I is the current in amperes (A).

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7
Q

Q: How is resistance caused?

A

A: Resistance occurs when electrons moving through a conductor collide with ions in the metal, making it more difficult for current to flow.

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7
Q

Q: What happens when resistors are added in series?

A

A: When resistors are added in series, the total resistance increases.

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8
Q

Q: What happens when resistors are added in parallel?

A

When resistors are added in parallel, the total resistance decreases. Resistors in parallel create less resistance than the same resistance in series.

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9
Q

Q: How does adding more resistors affect current in a circuit?

A

A: Adding more resistors reduces the current. In a series circuit, the current decreases with each additional resistor, while in parallel, the current increases.

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10
Q

Q: What happens to the total resistance in a series circuit?

A

A: The total resistance in a series circuit is the sum of the individual resistances.

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11
Q

Q: What happens to the current in a series circuit?

A

A: In a series circuit, the current is the same at every point.

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12
Q

Q: What is potential difference in a parallel circuit?

A

A: In a parallel circuit, the potential difference across each component is the same.

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13
Q

Q: What is the definition of current?

A

A: Current is the rate at which electrons flow through a circuit.

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14
Q

Q: What type of current does a battery produce?

A

A: A battery produces direct current (DC), where the current flows in one direction.

15
Q

Q: What is the difference between direct current (DC) and alternating current (AC)?

A

A: Direct current (DC) flows in one direction, while alternating current (AC) constantly changes direction, caused by most generators, and is used by mains electricity.

16
Q

Q: What is the voltage and frequency of mains electricity in the UK?

A

A: Mains electricity in the UK has a voltage of around 230V and a frequency of 50Hz.

16
Q

Q: What is a step-up transformer?

A

A: A step-up transformer increases the voltage in the circuit, which reduces current and minimizes energy loss in power lines.

17
Q

Q: What is a step-down transformer?

A

A: A step-down transformer decreases the voltage in the circuit, which increases current.

18
Q

Q: What does a transformer do to the power in a circuit?

A

A: A transformer does not change the power in the circuit; it changes the voltage and current, but the power remains the same.

19
Q

Q: What is the formula for electrical power?

A

A: Power = Current × Voltage

19
Q

Q: What is the purpose of the National Grid in the UK?

A

A: The National Grid connects power stations to factories and homes across the UK, ensuring electricity supply.

20
Q

Q: How does a step-up transformer reduce energy loss in the National Grid?

A

A: A step-up transformer increases the voltage, which decreases the current, reducing energy loss due to resistance in the power lines.

20
Q

Q: What is the formula used to relate charge, current, and time?

A

A: Q = I × T

20
Q

Q: What is resistance in terms of current flow?

A

A: Resistance is how easy or difficult it is for current to flow through a component. It is measured in ohms (Ω).

20
Q

Q: What is Ohm’s Law?

A

A: Ohm’s Law is V = IR, where V is the potential difference, I is the current, and R is the resistance.

21
Q

Q: What happens to the current in a circuit if the resistance increases?

A

A: If the resistance increases, the current decreases, assuming the voltage remains the same.

22
Q

Q: How does potential difference relate to energy transferred?

A

A: Potential difference (voltage) is the energy transferred per unit charge as it passes through a component.

23
Q

Q: What is a thermistor?

A

A: A thermistor is a type of resistor where the resistance changes with temperature.

24
Q

Q: What is a Light Dependent Resistor (LDR)?

A

A: An LDR is a component where the resistance changes with the light intensity.

25
Q

what is the formula linking potenial diffrence and current

A

potential differnece = current x reistance

physics (3 decks)

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