A as points Many electronics devices can be dangerous even a

A. (as points) Many electronics devices can be dangerous even ater they to a24 4. (15 ac circuit with a 160.-uF capacitor and a 1.10-M resistor an RC circuit source for a it be until the potential difference 160-uF capacitor and a 1.10-MQ resisgtor connected ne niure thed and soreisto aer they are shut of. Consider to below 70.0V? they are shut off. Consider to a 240.-V power long time and then disconnected and shorted, as shown in tnov ven after they are across the capacitor drops to drops own in the figure. How long will 5. (15 points) An uncharged capacitor and a resistor are connected in series to a battery, as in Figure below.TFT20V,6.00pF, and R 4 00r10s·find (a) the ti ne constant (b) the maximum charge on the capacitor, (c) the charge on the capacitor after potential différence across the resistor after 6.00 s, and (e) the current in the resistor si. t of the circuit, 4.00 s. (d) the at that time 0.6320;

Solution

4.

Time Constant

T=RC =(1.1*10⁶)(160*10^-6)=176 s

In a RC circuit Voltage as a function of time for discharging of capacitor is

V=V_maxe^-t/T

70 =240e^-t/176

-t/176 =Ln(240/70)

t=216.86 s

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5.

a)

Time Constant

T=RC=(6*10^-6)(4*10⁵) =2.4 s

b)

Maximum charge on the capacitor is

Q_max=CV =6u*12 =72 uC

c)

In a RC circuit charge as a function of time is given by

Q=Q_max(1-e^-t/T)

Q=72(1-e^-4/2.4)

Q=58.4 uC

d)

Voltage across the resistor is given by

V_R=Ve^-t/T

V_R = 12e^-6/2.4=0.985 Volts

e)

Current in the resistor

I=V_R/R =0.985/(4*10⁵)

I=2.46*10^-6 A or 2.46 uA