Part of an electric circuit is shown in the figure below.
A component is missing from the circuit in the figure above. Complete the circuit diagram in the figure by adding the circuit symbol for the missing component, correctly connected.
The circuit is used to produce half-wave rectification of an alternating voltage of potential difference (p.d.) 
. The output p.d. across the 
resistor is 
.
The graph below shows the variation with time 
of .
The graph below shows the variation with of
Determine the frequency of .
Show that the time constant 
for the discharge of the capacitor through the resistor is 
.
Calculate the capacitance of 
. Give a unit with your answer.
