V/R = total current flowing through circuit
Where R stands for total resistance.
I = 12/6 = 2 amp
Difference in potential across R1 = R1I = 8V
The combination of three resistors R1, R2, and R3 is shown in the circuit schematic below the total current in the circuit, the potential difference between R1 and R2
The combination of three resistors R1, R2, and R3 is shown in the circuit schematic below the total current in the circuit, the potential difference between R1 and R2