A capacitor C is charged using a supply of e.m.f. 
. It is then discharged through a resistor R. The circuit is shown in the figure below.
The variation with time 
of the potential difference 
across the resistor 
during the discharge of the capacitor is shown in the graph above.
During the first 
of the discharge of the capacitor, 
of energy is transferred to the resistor . Show that the capacitance of the capacitor C is 
.
