What happens to the total resistance of an electric circuit when an additional resistor is connected in parallel with an existing resistor?
Answer and explanation
Correct answer: A. Total resistance decreases
- Step 1: For parallel resistors: 1/R_total = 1/R1 + 1/R2.
- Step 2: Adding a parallel path provides an additional branch for electric current flow.
- Step 3: Because 1/R_total > 1/R1, R_total is strictly less than the smallest individual resistance in the combination.
Answer
Total resistance decreases.
Why not the others: 'Total resistance increases' describes resistors added in series; 'Total resistance remains unchanged' applies only if the branch carries zero conductance; 'Total resistance doubles' is false because conductance increases.
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