The resistance of the three arms of the balanced wheat stone bridge is 50 ohms. The resistance in the 4 ohm range is:
Correct answer: B. 50 ohm
- A. 25 ohm
- B. 50 ohm
- C. 75 ohm
- D. 100 ohm
Explanation
In a balanced Wheatstone bridge, the ratio of the resistances in one arm is equal to the ratio of the resistances in the other arm, expressed as X = (R * Q) / P. With all three known resistances being 50 ohms, the unknown resistance X also calculates to be 50 ohms, thereby maintaining the balance. The other options do not satisfy this relationship and would unbalance the bridge.
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About Resistance and Resistivity
Resistance measures opposition to current in a conductor and follows R = V/I for an ohmic conductor, while resistivity is an intrinsic property of the material. Questions use R = ρL/A, examine effects of length, cross-sectional area and temperature, and distinguish resistance, resistivity, conductance and conductivity.
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