Question

A series of circuit consisting of an uncharged 2.0-

Answer 1

For the charging current the formula is the standard

For charging the capacitor use

One time constant is where t=CR

Let ; then = 0.37 I_o

At t = infinity, Q = Qmax, meaning that the capacitor is fully charged.

Q_max = Q₀ = CV = 2*10^-6 * 100

= 2* 10^-4 C

I_ois the current throught the circuit when t = 0

10-MW = 10 * 10⁶ = (100)² / R

R = 1 * 10 ^-3 ohm.

So I_o = V/R = 100/1 * 10 ^-3

= 100000 A

a) For one time constant ;

I = 0.37 I_o

= 37000 A

Q = Q₀ (1- 0.37)

= 1.26 * 10^-4

B)

Q / Q_max = 0.90

Q = 0.90 Q_max = 0.90 * 2* 10^-4

= 1.8 * 10^-4

As ( 1 - e^t/RC ) = 0.90

t = 2.30 RC

Sun. the value of t in  

I = I_o * 0.100

= 100000 * 0.100258

= 10025.88 A