A cell of electromotive force 
and internal resistance 
is connected to an external resistor, as shown.
The current in the circuit is 
and the potential difference (p.d.) across the external resistor is 
. In the equation 
, what does the term 
represent?
electrical energy per unit charge lost in the cell
electrical energy per unit charge lost in the complete circuit
electrical energy per unit charge lost in the connecting wire
electrical energy per unit charge lost in the external resistor
