<P> Find the equivalent resistance in loop 1 and hence find the current in the loop . Use Ohm's Law to find the potential drop across the resistance C. The resistor B does not affect the open circuit voltage . Since no current is flowing through it, there is no potential drop across it . So we can easily ignore it . </P> <P> Therefore, the potential drop across the resistance C is V . </P> <P> This is just an example . Many other ways can be used . </P>

Why open circuit current is equal to zero