Question

A current I flows through a resistor with R = 333 Ω, and two inductors in parallel with L₁ = 2 Henry and L₂ = 4 Henry as shown in the Figure. At a time when the current I = 1.0 milliAmps and is changing at a rate dI/dt = -1.0 A/s, what is the potential difference V_B-V_A (in Volts)?

Answer 1

Moving in the direction of the current flow we have

since for inductors in parallel you add the inverses. Thus, L_eff  = 1.33 H and

so that, V_B-V_A = -0.333 V +1.33 V = 1 V.