MHT CET · Physics · Current Electricity
In a potentiometer experiment, the null point is obtained on \(7^{\text {th }}\) wire for given cell. To shift the null point on \(9^{\text {th }}\) wire for the same cell what should we do?
- A Decrease applied e.m.f.
- B Increase resistance in main circuit
- C Attach resistance in series with a cell
- D Decrease resistance in main circuit
Answer & Solution
Correct Answer
(B) Increase resistance in main circuit
Step-by-step Solution
Detailed explanation
Potential gradient,
\(\left(\frac{\Delta V}{L}\right)=\frac{\left[\frac{E R}{\left(R+R^{\prime}\right)}\right]}{L}\)
To increase the balancing length, we need to decrease the potential gradient. Hence, we have to increase the resistance in main circuit.
\(\left(\frac{\Delta V}{L}\right)=\frac{\left[\frac{E R}{\left(R+R^{\prime}\right)}\right]}{L}\)
To increase the balancing length, we need to decrease the potential gradient. Hence, we have to increase the resistance in main circuit.
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