EMI Flashcards
What does EMI stand for in the context of physics?
Electromagnetic Induction
True or False: Faraday’s law of electromagnetic induction states that the induced EMF in a closed loop is directly proportional to the rate of change of magnetic flux through the loop.
True
Fill in the blank: The unit of magnetic flux is __________.
Weber
What is the formula for Faraday’s law of electromagnetic induction?
EMF = -dΦ/dt
Define Lenz’s Law.
Lenz’s Law states that the direction of the induced current is such that it opposes the change in magnetic flux that produced it.
What is the principle behind a transformer?
A transformer operates on the principle of electromagnetic induction to transfer electrical energy between two or more circuits.
What is the relationship between primary and secondary voltage in an ideal transformer?
Vp/Vs = Np/Ns, where Vp is primary voltage, Vs is secondary voltage, Np is number of turns in primary coil, and Ns is number of turns in secondary coil.
True or False: The induced EMF can be generated by a stationary magnet and a moving coil.
True
What is self-induction?
Self-induction is the phenomenon where a changing current in a coil induces an EMF in the same coil.
What is mutual induction?
Mutual induction is the phenomenon where a changing current in one coil induces an EMF in a nearby coil.
Fill in the blank: The law of electromagnetic induction was discovered by __________.
Michael Faraday
What is the unit of induced EMF?
Volt
Define magnetic flux.
Magnetic flux is the product of the magnetic field and the area perpendicular to the field through which it passes.
What is the formula for calculating magnetic flux?
Φ = B · A · cos(θ)
True or False: A generator converts mechanical energy into electrical energy.
True
What is the role of the commutator in a DC generator?
The commutator reverses the direction of current flow in the coil, ensuring a unidirectional output.
What type of current do AC generators produce?
Alternating current (AC)
What is the effect of increasing the number of turns in a coil on the induced EMF?
Increasing the number of turns increases the induced EMF.
Fill in the blank: The phenomenon of induction is used in __________ applications.
wireless charging
What is the principle of operation of an inductor?
An inductor stores energy in a magnetic field when an electric current flows through it.
True or False: The induced current will always flow in the direction of the applied magnetic field.
False
What is the significance of the negative sign in Faraday’s law?
The negative sign indicates that the induced EMF opposes the change in magnetic flux.
What happens to the magnetic field when current is reduced in a coil?
The magnetic field strength decreases.
Define eddy currents.
Eddy currents are loops of electric current induced within conductors by a changing magnetic field.
