Magnetic Fields Flashcards
What is a magnetic field?
A magnetic field is a region around a magnet where magnetic forces can be detected.
True or False: Magnetic fields only exist around permanent magnets.
False
Fill in the blank: The unit of magnetic field strength is ______.
Tesla
What is the direction of the magnetic field around a straight current-carrying conductor?
The magnetic field forms concentric circles around the conductor.
What is the right-hand rule used for in electromagnetism?
It is used to determine the direction of the magnetic field around a current-carrying conductor.
What is the formula for the magnetic field strength (B) around a long straight conductor?
B = (μ₀ * I) / (2πr)
What does the symbol μ₀ represent?
The permeability of free space.
True or False: The magnetic field inside a solenoid is uniform.
True
What is the formula for the magnetic field strength inside a solenoid?
B = μ₀ * (n * I)
Fill in the blank: The number of turns per unit length of a solenoid is called ______.
turns density (n)
What is the effect of increasing the current in a solenoid on its magnetic field strength?
It increases the magnetic field strength.
What is the magnetic field shape around a bar magnet?
The magnetic field lines emerge from the north pole and enter the south pole, forming closed loops.
What is electromagnetic induction?
The process of generating an electromotive force (EMF) by changing the magnetic field around a conductor.
What is Faraday’s law of electromagnetic induction?
The induced EMF in a circuit is directly proportional to the rate of change of magnetic flux through the circuit.
Fill in the blank: The unit of magnetic flux is ______.
Weber
What is Lenz’s law?
It states that the direction of an induced current is such that it opposes the change in magnetic flux that produced it.
True or False: A changing magnetic field can induce a current in a nearby conductor.
True
What is the formula for magnetic flux (Φ)?
Φ = B * A * cos(θ)
What does θ represent in the magnetic flux formula?
The angle between the magnetic field lines and the normal to the surface.
What is the principle of operation of a transformer?
It operates on the principle of electromagnetic induction to transfer electrical energy between two circuits.
What is the turns ratio in a transformer?
The ratio of the number of turns in the primary coil to the number of turns in the secondary coil.
What happens to the voltage in a step-up transformer?
The voltage increases while the current decreases.
What happens to the voltage in a step-down transformer?
The voltage decreases while the current increases.
What is a magnetic field line?
A line that represents the direction and strength of a magnetic field.
