Physics- Topic 19 ( Capacitance )

Capacitance

Is the change stored per unit potential difference

The devices which store energy are known as capacitors

C = Q/V [C]= farads

Derive formula for combine capacitors in Series

Derive formula for combine capacitors in parallel

Finding work done from a voltage vs charge stored graph

Workdone is area under the graph

Finding electric potential energy stored in capacitor

W = ½ QV = ½ CV² = ½ Q²/C

The average potential difference is equal to half the maximum potential difference

Time Constant for a capacitor discharging through a resistor

Is the measure of how quickly a capacitor discharges

T = RC

larger t - slower discharge

lower t - faster discharge

Graph of Potential difference / Charge / Current Vs Time

They all are identical exponential graphs where by when t = 0, V=V₀ , I=I₀ , and Q=Q₀

They start at the X₀ and then decreases exponentially leading towards zero however X = 0 is an asymptote hence it will not cross the x-axis

The General decay formula that can be used for charge, potential difference and the current

X = X₀e^-t/RC