A diode allows current to flow in one direction only ; used to convert AC to DC current.

What is the function of a variable resistor ?

A variable resistor has a slider that can be used to change its resistance; commonly used in dimmer switches and volume controls.

How does the resistance of a thermistor change as temperature increases?

As temperature increases, the resistance of a thermistor decreases (and vice versa).

How does the resistance of a light-dependent resistor (LDR) change as light intensity increases?

As light intensity increases, the resistance of an LDR decreases (and vice versa).

How are an ammeter and a voltmeter connected differently within a circuit?

An ammeter is connected in series with the component A voltmeter is connected in parallel with the component

A light-emitting diode (LED) is equivalent to a .......... and emits light when a current passes through it.

A light-emitting diode (LED) is equivalent to a diode and emits light when a current passes through it.

True or False? A closed switch stops current from flowing in a circuit.

False. A closed switch allows current to flow; an open switch stops current from flowing.

For current to flow through a diode in a circuit, how must the diode be oriented relative to the direction of conventional current?

The diode must be forward-biased , pointing in the same direction as conventional current flow (from positive to negative ).

Define electromotive force (e.m.f) .

Electromotive force (e.m.f) is the amount of energy transferred per coulomb of charge when charge passes through a power supply.

Define potential difference .

Potential difference is the energy transferred per unit charge, measuring the energy transferred out of the circuit via the components.

What is the key difference between e.m.f and potential difference in terms of energy transfer?

e.m.f measures energy transferred into the circuit by the power source, while potential difference measures energy transferred out of the circuit by the components.

How can the e.m.f of a cell be measured experimentally?

By connecting a high-resistance voltmeter across the terminals of the cell in an open circuit (no current flowing).

e.m.f is a measure of the energy transferred .......... the circuit by the power source.

e.m.f is a measure of the energy transferred into the circuit by the power source.

True or False? The e.m.f of a cell is equal to its terminal potential difference when current is flowing through it.

False. E.m.f equals the terminal p.d. only when no current is flowing ; when current flows, some p.d. is lost across the internal resistance.

Define internal resistance ( r ).

Internal resistance is the resistance between the terminals of a power supply, causing energy loss as charge circulates inside it.

Why does a cell become warm after a period of use?

The internal resistance of the cell causes energy to be dissipated from the power supply itself as charge circulates.

Lost volts = e.m.f − ..........

Lost volts = e.m.f − terminal p.d.

True or False? The terminal potential difference of a cell is equal to its e.m.f when current flows through it.

False. Some of the e.m.f is lost across the internal resistance (lost volts), so the terminal p.d. is less than the e.m.f when current flows.

A LevelPhysicsCambridge (CIE)Flashcards10. D.C. CircuitsPractical Circuits

Practical Circuits (Cambridge (CIE) A Level Physics): Flashcards

Exam code: 9702

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Define diode.

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Cards in this collection (21)

Define diode.
A diode allows current to flow in one direction only; used to convert AC to DC current.
What is the function of a variable resistor?
A variable resistor has a slider that can be used to change its resistance; commonly used in dimmer switches and volume controls.
How does the resistance of a thermistor change as temperature increases?
As temperature increases, the resistance of a thermistor decreases (and vice versa).
How does the resistance of a light-dependent resistor (LDR) change as light intensity increases?
As light intensity increases, the resistance of an LDR decreases (and vice versa).
How are an ammeter and a voltmeter connected differently within a circuit?
- An ammeter is connected in series with the component
- A voltmeter is connected in parallel with the component
A light-emitting diode (LED) is equivalent to a .......... and emits light when a current passes through it.
A light-emitting diode (LED) is equivalent to a diode and emits light when a current passes through it.
True or False?
A closed switch stops current from flowing in a circuit.
False.
A closed switch allows current to flow; an open switch stops current from flowing.
For current to flow through a diode in a circuit, how must the diode be oriented relative to the direction of conventional current?
The diode must be forward-biased, pointing in the same direction as conventional current flow (from positive to negative).
Define electromotive force (e.m.f).
Electromotive force (e.m.f) is the amount of energy transferred per coulomb of charge when charge passes through a power supply.
Define potential difference.
Potential difference is the energy transferred per unit charge, measuring the energy transferred out of the circuit via the components.
What is the key difference between e.m.f and potential difference in terms of energy transfer?
e.m.f measures energy transferred into the circuit by the power source, while potential difference measures energy transferred out of the circuit by the components.
How can the e.m.f of a cell be measured experimentally?
By connecting a high-resistance voltmeter across the terminals of the cell in an open circuit (no current flowing).
e.m.f is a measure of the energy transferred .......... the circuit by the power source.
e.m.f is a measure of the energy transferred into the circuit by the power source.
True or False?
The e.m.f of a cell is equal to its terminal potential difference when current is flowing through it.
False.
E.m.f equals the terminal p.d. only when no current is flowing; when current flows, some p.d. is lost across the internal resistance.
Define internal resistance (r).
Internal resistance is the resistance between the terminals of a power supply, causing energy loss as charge circulates inside it.
What is the equation for lost volts in terms of current and internal resistance?
$lost volts = I r$
What is the equation for terminal potential difference?
$V_{R} = I R$
State the equation relating e.m.f, current, load resistance and internal resistance.
$E = I (R + r)$
Why does a cell become warm after a period of use?
The internal resistance of the cell causes energy to be dissipated from the power supply itself as charge circulates.
Lost volts = e.m.f − ..........
Lost volts = e.m.f − terminal p.d.
True or False?
The terminal potential difference of a cell is equal to its e.m.f when current flows through it.
False.
Some of the e.m.f is lost across the internal resistance (lost volts), so the terminal p.d. is less than the e.m.f when current flows.

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