In a balanced Wheatstone bridge with four arms P, Q, R, and S, what condition holds?
Answer and explanation
Correct answer: D. P / Q = R / S
- Step 1: When the bridge is balanced, no current flows through the central galvanometer (potential at intermediate nodes is equal). Step 2. This requires the ratio of adjacent resistances to be equal: P / Q = R / S. Answer: P / Q = R / S. Why not the others: Product equality is false; sum equality is false; P / R = S / Q inverts the right side.
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