A capacitor C is charged so that the potential difference (p.d.) 
across its terminals is 
. The capacitor is connected into the circuit shown in the figure below.
The switch is initially open. The switch is closed at time 
.
The graph below shows the variation of with the charge 
on the plates of capacitor C as the capacitor discharges.
Determine the capacitance of capacitor C. Give a unit with your answer.
The graph below shows the variation with 
of 
.
Show that, when is equal to one time constant, the value of is equal to 
.
Determine the time constant 
of the circuit in the figure shown above.
Calculate the resistance of resistor 
.
.
.
.
