A flexible circular loop has radius r(t)=r₀(1+αt) and lies in a uniform perpendicular field B(t)=B₀(1+βt). What is the magnitude of induced EMF at t=0?
Options

Question

A flexible circular loop has radius r(t)=r₀(1+αt) and lies in a uniform perpendicular field B(t)=B₀(1+βt). What is the magnitude of induced EMF at t=0?

G1 Physics · Accepted Answer

Φ=Bπr². At t=0, dΦ/dt=πB₀r₀²β+2πB₀r₀²α=πB₀r₀²(β+2α). Take the magnitude.