Question:hard

The equivalent inductance between A and B is equal to

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Trace the wires: all four inductors end up connected directly between A and B, so they are in parallel.
Updated On: Oct 1, 2026
  • \(10\) H
  • \(5\) H
  • \(\frac{12}{25}\) H
  • \(\frac{2}{5}\) H
Show Solution

The Correct Option is C

Solution and Explanation

Step 1: Merge the equal-potential points:
Call the node tied to A by wires "node A" and the node tied to B by wires "node B".
Node A includes: terminal A, the top wire, the right end of the 3 H coil, and the left end of the 4 H coil.
Node B includes: terminal B, the bottom wire, and the junction between the 1 H and 3 H coils.

Step 2: Place each inductor:
1 H: A to node B. 2 H: top wire (node A) to the junction (node B). 3 H: junction (node B) to the right end (node A). 4 H: node A to B.
So all four sit between node A and node B.

Step 3: Add reciprocals:
$\dfrac{1}{L} = 1 + 0.5 + 0.333 + 0.25 = 2.083 = \dfrac{25}{12}$, so $L = \dfrac{12}{25}$ H $= 0.48$ H.

Final Answer:
Option (C). \[ \boxed{\frac{12}{25}\text{ H (C)}} \]
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