In a parallel circuit, if one branch becomes open (infinite resistance), what happens to the current in the remaining branches?

• A. The current in the other branches remains the same; the total current decreases.
• B. The current in the other branches increases.
• C. The current in the others becomes zero.
• D. The current divides equally among all branches including the open one.

Answer: (A)

In a parallel circuit, each branch sees the same supply voltage. The current through a branch is determined by I = V/R for that branch. If one branch becomes open, its resistance goes to infinity, so the current in that branch becomes zero and effectively disappears from the circuit. The voltage across the remaining branches stays the same, so their currents don’t change. Since one path no longer draws current, the total current drawn from the source decreases, while the currents in the remaining branches stay the same. The open branch cannot share current with the others.