How do voltage and current behave in a parallel circuit?

How do voltage and current behave in a parallel circuit?

• A. Voltage stays the same, current divides proportionally.
• B. Current stays the same, voltage divides proportionally.
• C. Voltage and current both stay the same.
• D. Voltage changes across branches.

Answer: (A)

In a parallel circuit, all branches connect to the same two nodes, so the voltage across every branch is the same as the source voltage. That constant voltage across each path is why the statement makes sense. The current in each branch, however, depends on that same voltage and each branch’s resistance, via I = V/R. Because each branch can have a different resistance, the currents through the branches aren’t all equal—lower resistance means more current, higher resistance means less. The total current supplied by the source is the sum of the branch currents. Conceptually, the current distribution is proportional to each branch’s conductance (1/R). So the share of the total current that flows through a given branch is proportional to how easily that branch conducts. If all branches had the same resistance, they would share the current equally. The other statements don’t fit: current isn’t the same in every branch in parallel, and voltage doesn’t vary between branches in parallel.

In a parallel circuit, all branches connect to the same two nodes, so the voltage across every branch is the same as the source voltage. That constant voltage across each path is why the statement makes sense.

The current in each branch, however, depends on that same voltage and each branch’s resistance, via I = V/R. Because each branch can have a different resistance, the currents through the branches aren’t all equal—lower resistance means more current, higher resistance means less. The total current supplied by the source is the sum of the branch currents.

Conceptually, the current distribution is proportional to each branch’s conductance (1/R). So the share of the total current that flows through a given branch is proportional to how easily that branch conducts. If all branches had the same resistance, they would share the current equally.

The other statements don’t fit: current isn’t the same in every branch in parallel, and voltage doesn’t vary between branches in parallel.