Magnetism Flashcards
What is a magnetic field?
A region around a magnet where magnetic forces act.
What is the shape of the magnetic field around a bar magnet?
The magnetic field around a bar magnet is a series of concentric loops running from the north pole to the south pole.
What do iron filings reveal about magnetic fields?
Iron filings form patterns along the magnetic field lines, showing the direction and shape of the magnetic field.
What is a magnetic field line?
A line that shows the direction of the magnetic force, pointing from the north pole to the south pole outside the magnet.
What is the force between two magnets?
Like poles of magnets repel each other, while opposite poles attract each other.
What is the Earth’s magnetic field?
Earth acts like a giant magnet with a magnetic field that extends from the south pole to the north pole.
What is electromagnetism?
The interaction between electric currents and magnetic fields.
How can you increase the strength of an electromagnet?
Increase the number of coils, increase the current, or use a ferromagnetic core (like iron).
What is the right-hand rule for electromagnetic force?
When you hold the wire with your right hand, with the thumb pointing in the direction of current, the fingers curl in the direction of the magnetic field.
What is a solenoid?
A coil of wire that produces a magnetic field when an electric current passes through it.
What is the magnetic field inside a solenoid?
The magnetic field inside a solenoid is uniform and strong, with field lines parallel to the solenoid’s axis.
What happens when a current-carrying wire is placed in a magnetic field?
A force is exerted on the wire, causing it to move, which is the basis of how motors work.
What is the motor effect?
The force experienced by a current-carrying conductor in a magnetic field.
What factors affect the size of the force on a current-carrying conductor in a magnetic field?
The strength of the magnetic field, the size of the current, and the angle between the conductor and the magnetic field.
What is Fleming’s Left-Hand Rule?
A rule used to determine the direction of force on a current-carrying conductor in a magnetic field. The thumb is the direction of the force, the first finger is the magnetic field, and the second finger is the current.
What is a transformer?
A device that changes the voltage of an alternating current (AC) by using two coils of wire and a magnetic field.
What is the relationship between the number of turns on the primary and secondary coils in a transformer?
The voltage ratio is equal to the turns ratio:
What does the term “alternating current (AC)” mean?
An electric current that reverses direction periodically.
What is an electromagnet?
A magnet created by an electric current flowing through a coil of wire, often wrapped around a core material like iron.
What is the difference between a permanent magnet and an electromagnet?
A permanent magnet produces its own magnetic field, while an electromagnet’s magnetic field is only present when an electric current is passing through the coil.
