test 2: induction & faraday's law mcq

according to faraday’s law, an emf is induced whenever…

A) a magnetic field exists

B) magnetic flux through a loop changes

C) current is constant

D) electric charge increases

E) resistance changes

faraday’s law, ϵ = |-NΔΦ|/Δt → ΔΦ = BAcosθ where if B, A, or cosθ change the flux changes in faraday’s law

B) magnetic flux through a loop changes

faraday’s law & flux

ϵ = |-NΔΦ|/Δt

ΔΦ = BAcosθ where if B, A, or cosθ change the flux changes

lenz’ law states that the induced current…

A) always increases magnetic flux

B) always flows clockwise

C) opposes the change in magnetic flux

D) produces zero magnetic field

E) depends on only resistance

lenz’ law opposes to maintain equilibrium

C) always opposes the change in magnetic flux

emf of a metal rod/conductor through a magnetic field

ϵ = Blv

a straight conductor of wire 0.40m moves perpendicular to a 0.60T magnetic field at 5.0m/s. the induced emf is…

A) 0.40V

B) 0.72

C) 1.2V

D) 2.0V

E) 3.0V

emf, ϵ = Blv

C) 1.2V

a loop of wire enters a region of uniform magnetic field. the induced current exists…

A) only while the magnetic flux through the loop is changing

B) only after the loop is completely inside the field

C) only when the magnetic loops field becomes zero

D) only if the loop is superconducting

E) only when the loop stops moving

current only changes when the magnetic flux is changing

A) only while the magnetic flux through the loop is changing