If a branch is removed from a parallel circuit of three equal resistors, what happens to the total resistance?

If a branch is removed from a parallel circuit of three equal resistors, what happens to the total resistance?

• A. decreases
• B. stays the same
• C. increases
• D. becomes zero

Answer: (C)

In parallel circuits, the total resistance depends on how many paths there are for current to take. More parallel paths lower the overall resistance; fewer paths raise it. With three identical resistors in parallel, the equivalent resistance is one third of a single resistor. If you remove one branch, you’re left with two identical resistors in parallel, giving an equivalent resistance of one half of a single resistor. Since one-half is larger than one-third, the total resistance increases. At a fixed voltage, that means the total current decreases accordingly.

In parallel circuits, the total resistance depends on how many paths there are for current to take. More parallel paths lower the overall resistance; fewer paths raise it. With three identical resistors in parallel, the equivalent resistance is one third of a single resistor. If you remove one branch, you’re left with two identical resistors in parallel, giving an equivalent resistance of one half of a single resistor. Since one-half is larger than one-third, the total resistance increases. At a fixed voltage, that means the total current decreases accordingly.