These drawings illustrate various situations in which a magnetic field is directed out of the screen, and there is a corresponding magnetic flux through a single loop. In drawings (a) through (d), the magnetic field has a constant magnitude of B=33.2mTB=33.2mT. The radius and the resistance of the ring in drawings (c) and (e) are 7.3cm7.3cm and 4.6Ω4.6Ω, respectively. In drawings (e) and (f), the rate at which the magnetic field is either increasing or decreasing has magnitude ΔB/Δt=7mT/sΔB/Δt=7mT/s.
In drawing (a), a moving bar slides along two conductive rails that are connected by a wire at the left end. Use Lenz's law to determine the direction of the induced current in the closed loop.