In a parallel circuit, when a branch (which could contain a resistor, a bulb, or another load) is added, the total resistance of the circuit actually decreases. This is due to the nature of parallel connections, where each additional branch provides an alternative path for current to flow.
Here’s how it affects the circuit:
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Total Resistance Decreases: Adding a branch lowers the overall resistance of the circuit. This happens because the reciprocal formula for total resistance in a parallel circuit (1/R_total = 1/R1 + 1/R2 + ...) shows that adding more branches leads to a lower total resistance.
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Current Increases: With the decrease in total resistance, and assuming the voltage from the power source remains constant (according to Ohm's Law: V = I * R), the total current in the circuit increases.
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Brightness of Bulbs: If the circuit contains bulbs, the increased current caused by the reduced total resistance means that bulbs will shine brighter since there is more current flowing through each branch.
Therefore, the correct statement would be: The total resistance decreases, so the current in the circuit increases. If bulbs are present, they would shine brighter due to the higher current.