Chapter 18: Electromagnetic Induction Flashcards
(20 cards)
What is electromagnetic induction?
“Electromagnetic induction is the process by which a changing magnetic field induces an electromotive force (emf) in a conductor.”
What is Faraday’s law of induction?
“Faraday’s law states that the induced emf in a closed loop is directly proportional to the rate of change of the magnetic flux through the loop: ε = -dΦ_B/dt.”
What is Lenz’s law?
“Lenz’s law states that the direction of the induced current or emf opposes the change in magnetic flux that caused it.”
What is magnetic flux?
“Magnetic flux (Φ_B) is the product of the magnetic field (B) and the area (A) through which the magnetic field lines pass
What is the unit of magnetic flux?
“The unit of magnetic flux is the weber (Wb)
What is the formula for induced emf?
“The formula for induced emf is ε = -dΦ_B/dt
What does the negative sign in Faraday’s law indicate?
“The negative sign in Faraday’s law indicates that the induced emf opposes the change in magnetic flux
What is the concept of mutual induction?
“Mutual induction is the phenomenon where a changing current in one coil induces an emf in a nearby coil.”
What is the formula for the induced emf in a coil?
“The induced emf in a coil with N turns is given by ε = -N (dΦ_B/dt)
What is self-induction?
“Self-induction is the process by which a changing current in a coil induces an emf in the same coil.”
What is the inductance of a coil?
“The inductance (L) of a coil is a measure of its ability to induce emf in response to a change in current
What is the unit of inductance?
“The unit of inductance is the henry (H)
What is the concept of a transformer?
“A transformer is a device that uses electromagnetic induction to change the voltage and current in an alternating current (AC) circuit.”
What is the equation for the transformer?
“The transformer equation relates the voltage and current on the primary and secondary coils: V₁/V₂ = N₁/N₂ = I₂/I₁
What is the efficiency of a transformer?
“The efficiency of a transformer is the ratio of the power output to the power input
What is the concept of eddy currents?
“Eddy currents are circulating currents induced in a conductor when it is exposed to a changing magnetic field. These currents cause energy losses in the form of heat.”
What is the purpose of laminated cores in transformers?
“Laminated cores in transformers reduce the effects of eddy currents
What is the concept of electromagnetic waves?
“Electromagnetic waves are waves of oscillating electric and magnetic fields that propagate through space and carry energy
What is the relationship between voltage and current in an RL circuit?
“In an RL circuit
What is the time constant (τ) of an RL circuit?
“The time constant (τ) of an RL circuit is the time required for the current to reach approximately 63% of its final value
