Electricity and Magnetism ETT Flashcards
What is the circuit symbol for an open switch?
What is the circuit symbol for a closed switch?
What is the circuit symbol for a cell?
What is the circuit symbol for a battery?
What is the circuit symbol for a resistor?
What is the circuit symbol for a variable resistor?
What is the circuit symbol for a lamp?
What is the circuit symbol for a fuse?
What is the circuit symbol for a voltmeter?
What is the circuit symbol for an ammeter?
What is current?
The rate of flow of charge
What type of circuit is shown in the image?
Series circuit
What equation links potential difference, current and voltage?
Potential difference = current x resistance
V = I R
For a given potential difference, what happens to the current when the resistance increases?
The current decreases.
What is the rule for current in a series circuit?
Current is the same everywhere in the circuit
What is the rule for potential difference in a series circuit?
Potential difference is shared between components.
Where should you place an ammeter to measure current through a component?
The ammeter should be placed in series with the component.
What is the rule for potential difference in a parallel circuit?
It is the same in each branch.
Where should you place a voltmeter to measure potential difference across a component?
The voltmeter should be placed parallel to the component.
What is the total resistance of the three resistors in series?
25 Ω
What is the rule for current in a parallel circuit?
Current is shared between the branches.
Name the equipment used to measure potential difference.
Voltmeter
What is meant by the term ‘resistance’?
How difficult it is for current to flow
In a parallel circuit, what happens to the total resistance when you add a resistor?
The total resistance decreases.
Name the equipment used to measure current.
Ammeter
When two insulating materials are rubbed together, what charge will the material that gains electrons have?
Negative
When certain insulating materials are rubbed together, what will be scraped off one and transferred onto the other?
Electrons
What do like charges do?
Repel
Name the force that causes a build up of static charge.
Friction
When two insulating materials are rubbed together, what charge will the material that loses electrons have?
Positive
Name the force exerted between charged objects.
Electrostatic
What do opposite charges do?
Attract
Name the three magnetic materials.
- Iron
- Cobalt
- Nickel
What happens when two ‘like’ poles are brought together?
They repel each other
Is magnetism an example of a contact or non-contact force?
Non-contact force
Draw the magnetic field lines around a bar magnet.
What happens when two opposite poles are brought together?
They attract each other
Complete the diagram to show the directions that the plotting compasses will point.
Draw the magnetic field around an electromagnet.
What happens when a current flows through a wire?
A magnetic field is produced
Describe the magnetic field lines in the middle of an electromagnet.
Strong and uniform
Give three ways in which you can increase the strength of an electromagnet.
- Increase the voltage
- Increase the number of coils on the wire
- Use a soft iron core in the middle
Give two advantages of an electromagnet over a permanent magnet?
- You can turn an electromagnet on and off.
- You can change the strength of the electromagnet
What causes the Earth to have a magnetic field?
Liquid iron in the Earth’s core
What two ways can be used to investigate magnetic field lines around a bar magnet?
- Sprinkle iron filings around the magnet
- Move a plotting compass around the magnet
