Wheatstone Bridge

To determine the unknown resistance in the meter bridge experiment, we analyze the given conditions and use the principle of the meter bridge. Given:
- Resistance in the left gap,
- Unknown resistance in the right gap,
- When the resistances are interchanged, the balancing point shifts by 10 cm.

Step 1: Initial Balancing Condition In the meter bridge, the balancing condition is: where is the balancing length from the left end. Initially:

Step 2: After Interchanging Resistances When the resistances are interchanged, the new balancing condition is: Here, the balancing length shifts by 10 cm, so the new balancing length is cm.

Step 3: Solve the Equations From the initial condition: From the interchanged condition:

Step 4: Equate the Two Expressions for
Simplify: Step 5: Calculate Using the initial condition: Final Answer: This corresponds to option (3).