Electricity Flashcards
What are the two different types of electric charge?
Positive and Negative
Like charges will ___ each other.
Repel
Opposite charges will ___ each other.
Attract
What particles are atoms made up of?
Protons
Neutrons
Electrons
What does it mean if an atom is neutral?
Same number of protons and electrons.
Define the electric current.
The electric current is the flow of electrons through a material.
What is an electrical current considered to be?
An electrical current is considered to be the flow of electrons/negative charges.
What is the smallest unit of electric charge?
One electron
What is current defined as?
The rate of flow of electric charge.
(The charge that passes a point in 1 second.)
What is the symbol and unit of Charge?
Symbol - Q
SI Unit - C (Coulomb)
What is the symbol and unit of current?
Symbol - I
SI Unit - A
What is the symbol and unit of time?
Symbol - t
SI Unit - s
What is the formula for calculating charge?
Q = It
—
Q - Charge (Coulombs)
I - Current (A)
t - Time (s)
What does a battery supply?
Direct current
What is a direct current?
A current in which charges move in only one direction.
What does a signal generator supply?
An alternating current.
How do the charges move in an alternating current?
In an alternating current, charges will move one way and then change direction.
What does the “UK mains supply” supply?
An alternating current at 230V with a frequency of 50Hz.
In an alternating current, what does Hz measure?
In an alternating current, Hz measures how many times the current changes direction every second.
What does the SIGNAL GENERATOR trace on an oscilloscope screen of current/time vary in?
The trace from the signal generator varies in AMPLITUDE on an oscilloscope screen.
What does the BATTERY trace on an oscilloscope screen of current/time vary in?
The trace from the battery does not vary on an oscilloscope screen. It remains CONSTANT.
The oscilloscope trace for an alternating current _____
varies in amplitude.
The oscilloscope trace for a direct current ____
remains constant.
From a power supply to an electrical component, what do electric circuits do?
Electric circuits transfer energy from a power supply to an electrical component.
Describe the structure of a series circuit.
In a series circuit, the electrons have only one path to flow through within the circuit.
A break anywhere in the circuit will cause the circuit to stop working.
Describe the structure of a parallel circuit.
In a parallel circuit, there are more than one path for electrons to flow through.
A break in one of the branches of the circuit will NOT affect the rest of the circuit.
All branches must be broken to stop the current.
What are cells and batteries used for?
Cells and batteries are used to supply energy to an electrical circuit.
What is the chemical change in cells and batteries?
The energy change in cells and batteries is CHEMICAL ENERGY to ELECTRICAL ENERGY.
What exists around an electrical charge?
An electric field.
(Magnet has magnetic field, etc)
Define an electrical field.
An electrical field is a place where a charged particle experiences a force.
What concept is responsible for the flow of electrons around an electrical circuit?
The electrical field.
In what direction does the force move across the ELECTRICAL FIELD LINES in a POSITIVE charge?
Away from the positive charge and towards the negative charge
In what direction does the force move across the ELECTRICAL FIELD LINES in a NEGATIVE charge?
Away from the negative charge and towards the positive charge
What are the field lines between two parallel plates called, and what does it mean?
A UNIFORM FIELD.
This means that all of the charged particles in the field will experience the same size of force.
How must a uniform field be drawn?
With STRAIGHT LINES which are an EQUAL DISTANCE apart.
The CLOSER the lines are to one another, the STRONGER the field.
In an electrical circuit, ___ is carried by electrons around the circuit and converted into others forms of ___ by the ____ in the circuit.
Electrical
Energy
Components
What is the “potential” of the electrons at any point in a circuit?
The POTENTIAL is the amount of electrical energy that the electrons carry at any point within the circuit.
What happens to electrical energy as electrons move between two points in a circuit?
The electrical energy is TRANSFERRED into other forms as electrons move between two points in a circuit.
Define “Potential Difference”.
Potential Difference (Voltage) is the energy that is transferred by 1 coulomb of charge.
Therefore, the POTENTIAL DIFFERENCE of the SUPPLY is a MEASURE of the ENERGY given to each COULOMB OF CHARGE in a circuit.
Describe the apperance of a voltmeter. (bc im too lazy to draw it xoxo)
Circle with V in the middle and a line through it.
Describe the apperance of an ammeter. (bc im too lazy to draw it xoxo)
Circle with A in the middle and a line through it.
Describe the apperance of a motor. (bc im too lazy to draw it xoxo)
Circle with M in the middle and a line through it.
Describe the apperance of a fuse. (bc im too lazy to draw it xoxo)
A rectangle with a horizontal line OVER it.
Describe the apperance of a resistor. (bc im too lazy to draw it xoxo)
A rectangle with a horizontal line BENEATH it.
Describe the apperance of a switch. (bc im too lazy to draw it xoxo)
Straight line
Straight line break and tilt up
Straight line continue flat
State three features relating to Current.
- Electrical current is measured in AMPERES (A)
- An AMMETER measures the size of an electrical current.
- An AMMETER is connected in SERIES of a circuit.
State three features relating to Voltage.
- Voltage is measured in Volts (V)
- Voltage is measured ACROSS THE CIRCUIT using a VOLTMETER.
- A voltmeter is connected in parallel.
(Voltage is always measured ACROSS a component)