You charge an initially uncharged 77.9-mf capacitor through a 35.9-Ï resistor by means of a 9.00-v battery having negligible internal resistance. find the time constant of the circuit. what is the charge of the capacitor 1.83 time constants after the circuit is closed? what is the charge after a long time?

Respuesta :

When a charged capacitor is connected to resistor, it discharges exponentially.
Charge on capacitor at any time t is given by,
[tex]Q = Q_{0}e^{ \frac{-t}{k} } [/tex]
 k = RC = time constant = 35.9 x 77.9 x 10⁻³ = 2.79 
plug t = 1.83 x k in above equation.
t = 5.1057 sec.
[tex]Q_{0} =[/tex] = CV = 77.9 x 10⁻³ x 9 = 0.7011 C.

plug values of [tex]Q_{0} =[/tex] and t in above equation to get Q
To calculate the charge after a long time, plug t= infinite in equation.