Advanced Higher Physics

Mandatory Course Key Areas - Aug 2018

Knowledge of the variation of current and potential difference with time in an RC circuit during charging and discharging.

Definition of the time constant for an RC circuit as the time to increase the charge stored by 63% of the difference between initial charge and full charge, or the time taken to discharge the capacitor to 37% of initial charge.

Use of an appropriate relationship to determine the time constant for an RC circuit.

\tau =\mathrm{RC}

Knowledge that, in an RC circuit, an uncharged capacitor can be considered to be fully charged after a time approximately equal to 5t .

Knowledge that, in an RC circuit, a fully charged capacitor can be considered to be fully discharged after a time approximately equal to 5t .

Graphical determination of the time constant for an RC circuit.

>Knowledge that capacitive reactance is the opposition of a capacitor to changing current. Use of appropriate relationships to solve problems involving capacitive reactance, voltage, current, frequency, and capacitance.

X_c=\frac{V}{I}

X_c=\frac{1}{\mathrm{2\pi fC}}

Knowledge of the growth and decay of current in a DC circuit containing an inductor.

Explanation of the self-inductance (inductance) of a coil.

Knowledge of Lenz’s law and its implications.

Definition of inductance and of back EMF.

Knowledge that energy is stored in the magnetic field around a current-carrying inductor.

Knowledge of the variation of current with frequency in an AC circuit containing an inductor.

Knowledge that inductive reactance is the opposition of an inductor to changing current.

Use of appropriate relationships to solve problems relating to inductive reactance, voltage, current, frequency, energy, and self-inductance (inductance).

\epsilon =\mathrm{-L}\frac{\mathrm{dI}}{\mathrm{dy}}

E=\frac{1}{2}{\mathrm{LI}}^2

X_L=\frac{V}{I}

X_L=\mathrm{2\pi fL}