A-LEVEL Physics: 5.1.1: Basics of Electricity (SaveMyExams) Flashcards
A Simple Electrical Circuit Requires: (2)
-A Conductor through which Current Can Flow.
-A Source of Potential Difference.
What is ‘Electrical Current’?
Electrical Current is the Rate of Flow of Electrical Charge.
Unit of Current:
Amperes, Amps (A)
Current = …
Charge / Time
I = ∆Q/∆t
Current Flows when a ___ is Formed. When is this?
Circuit.
This is when a Conductor, eg a Wire, Connects Two Oppositely Charged Terminals of a Source, eg a Cell.
When does Current Flow through a Circuit?
Current Flows when a Complete Circuit links the Oppositely Charged Terminals of a Cell, Inducing a Potential Difference.
Charge Flows through the ___ of a Circuit.
Components.
What Must a Circuit do in Order for a Charge to Flow?
For a Charge to Flow, a Circuit Must Connect the Positive & Negative Terminals of an Electrical Energy Source, Setting up a Potential Difference.
In Electric Circuits, the Current is the…
Net Flow of Electrons.
The Rate of Flow of Charge.
What is ‘Conventional Current’?
Conventional Current is the Net Flow of Charge from the Positive Terminal of a Cell to the Negative Terminal.
Conventional Current is the ___ of the Direction of Electron Flow. Explain why.
Opposite. Because Electrons are Negatively Charged, so they Flow from the Negative Terminal of a Cell to the Positive Terminal.
Conventional Current Flows from the ___ Terminal to the ___ Terminal of the Battery. Electrons Flow in the ___ Direction, due to their ___ Charge.
Positive, Negative. Opposite, Negative.
Current Can be Measured Using an…
Ammeter.
Ammeters Must be Connected in ___ With the Component in order to Measure the Current through it.
Series.
Ammeters Must be Connected in ___ with the Component being Measured. Why?
Series. Because the Current Through Components Connected in Series is the Same.
An Ammeter Can be Used to Measure the ___ Flowing Through a Component in a Circuit, & is Always Connected is ___.
Current, Series.
What is ‘Potential Difference’?
Potential Difference is the Electrical Work Done Per Unit Charge Flowing Between Two Points.
The Energy Transferred Per Unit Charge.
Unit of Potential Difference:
Voltage (V)
Potential Difference = …
Energy Transferred / Charge
V=E/Q
How does a Simple Cell Create a Potential Difference?
A Simple Cell Creates a Potential Difference by Setting Up Two Oppositely Charged Terminals: Positive Terminal & Negative Terminal.
How does a Potential Difference Cause a Current? (3)
-The Cell has a Positive Terminal, & a Negative Terminal.
-The Negatively Charged Electrons are Repelled by the Negative Terminal, & are Attracted to the Positive Terminal.
-Therefore, when a Wire is Connected Between the Two Terminals, the Potential Difference Causes the Net Flow of Electrons (Current).
Potential Difference Can be Measured Using a…
Voltmeter.
Voltmeters Must be Connected in ___ with the Component being Measured.
Parallel.
What does an ‘Ammeter’ do?
An Ammeter Measures the Current Flowing Through a Component Connected in Series.
What does a ‘Voltmeter’ do?
A Voltmeter Measures the Voltage Between Two Points in a Circuit, by being Connected in Parallel.
What is ‘Resistance’?
Resistance is the Opposition of a Component to the Flow of Electrical Current Through it.
Resistance = …
Voltage / Current
R=V/I
Unit of Resistance:
Ohms (Ω)
The Resistance of a Component Controls the Size of the ___ in the Circuit.
Current.
The Higher the Resistance, the ___ the Current that Can Flow.
Lower.
The Lower the Resistance, the ___ the Current that Can Flow.
Higher.
All Electrical Components have Some…
Resistance.
Why are Wires Often Made of Copper?
Because of its Low Electrical Resistance.
Hence, Copper is a Good Electrical Conductor.
