A precision function generator drives a current through a coil according to the…

PHYSICS · Multi-part · A Level · Physics · Electricity · Electricity

Problem

A precision function generator drives a current I(t)I(t) through a coil according to the sinusoidal relation I(t)=Ipeaksin⁡(ωt)I(t) = I_{\text{peak}} \sin(\omega t), starting at t=0t=0. • The peak current IpeakI_{\text{peak}} is 2.5 A. • The angular frequency ω\omega is 120π rad s−1120\pi\,\text{rad}\,\text{s}^{-1} (corresponding to a 60 Hz power signal). (a) Derive an algebraic expression for the total charge q(t)q(t) that has passed through the coil from time t=0t=0 up to an arbitrary time tt. (b) Using your result from part (a), calculate the exact amount of charge that passes through the coil during the first quarter of a complete cycle. (c) Determine the earliest time t1 Ct_{1\,\text{C}} at which exactly 1.0 C1.0\,\text{C} of charge has passed through the coil. (d) Over a full cycle (period TT), what is the net charge transported through the coil? Explain physically why this result makes sense in the context of alternating current.

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