NEET2026Physics
Q.
A uniform metallic wire having resistance 4 is bent to form a square loop (ABCD) (see figure). A resistance of 2 is connected between points B and D and a battery of 2 V is connected across points A and C as shown in the figure. Now the value of current (I) is :

- A
4 A
- B
4.5 A
- C
8 A
- D
2 A
Solution
Each side of the square has resistance . The two paths from A to C (A→B→C and A→D→C) each have resistance .
The 2 resistor between B and D acts as the galvanometer arm of a Wheatstone bridge. By symmetry the bridge is balanced and no current flows through this arm, so it can be ignored.
Net resistance: two 2 paths in parallel give .
A.
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