What is the voltage in a parallel circuit?

[erocored]

Potentials in points E, F, A, B are equal because there is no resistance. In my opinion, losses of potential energy in the resitors R1 and R2 are not equal (potential C ≠ potential G). Then why do we say that voltage in this circuit is the same?

 

[etotheipi]

Why not? Like you said, $\phi_A = \phi_B = \phi_E = \phi_F$, and likewise $\phi_C = \phi_D = \phi_G = \phi_H$. Then $V_{BC} = \phi_B - \phi_C$, and $V_{FG} = \phi_F - \phi_G$, and so $V_{BC} = V_{FG}$.

You might say that the voltages across each resistor, which are the differences in potential energy of a unit charge on either end of the resistor, are equal.

 

[erocored]

Why not? Like you said, $\phi_A = \phi_B = \phi_E = \phi_F$, and likewise $\phi_C = \phi_D = \phi_G = \phi_H$. Then $V_{BC} = \phi_B - \phi_C$, and $V_{FG} = \phi_F - \phi_G$, and so $V_{BC} = V_{FG}$.

You might say that the voltages across each resistor, which are the differences in potential energy of a unit charge on either end of the resistor, are equal.

Is it possible that potential C > potential G?

 

[etotheipi]

Is it possible that potential C > potential G?

Not in your diagram, no. Just look at the path $C \rightarrow D \rightarrow H \rightarrow G$. Each of those 3 wires have zero resistance, so have zero voltage across them.

 

[gmax137]

The fact that the voltages C and G are equal is what you use to determine the two currents I1 and I2. You could say the currents "adjust themselves" to achieve the same voltage drops.

 

[Dale]

In my opinion, losses of potential energy in the resitors R1 and R2 are not equal (potential C ≠ potential G).

The statement outside of the parentheses is true, and the statement in the parentheses is false. Remember that potential is not equal to potential energy but rather is equal to potential energy per charge.

Yes, the potential energy lost is different in the two resistors, but so is the amount of charge passing the two resistors. The potential energy lost per charge is the same. So the potential at C is equal to the potential at G.