Question

In a given circuit, AB is a uniform potentiometer wire. If the value of resistance ' \(R\) ' is slightly increased, the balance point

• A. shifts towards \(B\)
• B. shifts towards A
• C. will not change
• D. will not be obtained

Hint:

A larger R reduces the current in the wire, so the potential gradient falls and a longer wire is needed.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept
The potential gradient along the wire is \(k=\dfrac{V_{AB}}{L}\), where \(V_{AB}\) is the voltage across AB.

Step 2: Effect of increasing R
A larger \(R\) in series reduces the current in the wire, so the potential drop across AB and the gradient decrease.

Step 3: Balance point
At balance \(E_{1}=k\,l\). With a smaller \(k\), the length \(l\) must increase.

Step 4: Result
The balance point moves away from A, towards B.

Final Answer:
The balance point shifts towards B. \[ \boxed{\text{(A) }\text{shifts towards B}} \]