Potentiometer Sensitivity

Potentiometer sensitivity refers to the ability of a potentiometer to accurately measure changes in voltage. The sensitivity of a potentiometer can be increased by various factors. Among the given options, the correct answer is option 'B', which states that increasing the length of the potentiometer wire can increase its sensitivity.

Explanation

To understand why increasing the length of the potentiometer wire increases its sensitivity, let's first understand how a potentiometer works. A potentiometer consists of a long resistive wire with a sliding contact called the wiper. When a voltage is applied across the ends of the wire, a potential gradient is established along its length.

The wiper can be moved along the wire, and the voltage at the wiper position can be measured. By adjusting the position of the wiper, the potentiometer can be used to measure the unknown voltage or determine the ratio of two voltages.

When the length of the potentiometer wire is increased, the potential gradient along the wire becomes smaller. This means that for a given change in position of the wiper, the change in voltage measured will be larger. Therefore, increasing the length of the potentiometer wire increases its sensitivity.

Other Options

Let's also discuss the other options mentioned in the question and why they do not increase the sensitivity of the potentiometer:

a) Increasing the current in the potentiometer wire: Increasing the current does not directly affect the sensitivity of the potentiometer. The sensitivity of a potentiometer is determined by the potential gradient along the wire, which is a function of the voltage applied and the length of the wire.

c) Decreasing the length of the potentiometer wire: Decreasing the length of the potentiometer wire will actually decrease its sensitivity. A shorter wire will have a steeper potential gradient, meaning that a small change in position of the wiper will result in a larger change in voltage. This decreases the sensitivity of the potentiometer.

d) Replacing the standard cell by a regulated power supply: The power supply used does not directly affect the sensitivity of the potentiometer. As long as the voltage applied is within the range of the potentiometer, the sensitivity will not be affected.

Conclusion

In conclusion, the sensitivity of a potentiometer can be increased by increasing the length of the potentiometer wire. This is because a longer wire results in a smaller potential gradient, making the potentiometer more sensitive to changes in voltage.