Physics Topic: Currents

  1. show an understanding that electric current is the rate of flow of charge and solve problems using I = Q/t

  2. derive and use the equation I = nAvq for a current-carrying conductor, where n is the number density of charge carriers and v is the drift velocity

  3. recall and solve problems using the equation for potential difference in terms of electrical work done per unit charge, V = W/Q

  4. recall and solve problems using the equations for electrical power P = VI,  P = I 2R and P = V2/R

  5. distinguish between electromotive force (e.m.f.) and potential difference (p.d.) using energy considerations

  6. show an understanding of and use the terms period, frequency, peak value and root-mean-square (r.m.s.) value as applied to an alternating current or voltage

  7. represent a sinusoidal alternating current or voltage by an equation of the form x = x0 sin ωt

  8. deduce that the mean power in a resistive load is half the maximum (peak) power for a sinusoidal alternating current

  9. distinguish between r.m.s. and peak values, and recall and use Irms = I0/√2 and Vrms = V0/√2 for the sinusoidal case

  10. explain the use of a single diode for the half-wave rectification of an alternating current.