If a potentiometer is used to compare two emfs, what is the key requirement for
Practice Questions
Q1
If a potentiometer is used to compare two emfs, what is the key requirement for the two circuits?
They must have the same resistance
They must have the same length of wire
They must be connected in series
They must have the same potential gradient
Questions & Step-by-Step Solutions
If a potentiometer is used to compare two emfs, what is the key requirement for the two circuits?
Correct Answer: Both circuits must have the same potential gradient.
Step 1: Understand what a potentiometer is. It is a device used to measure voltage (emf) by comparing it to a known reference.
Step 2: Know that when comparing two emfs, you need to set up two circuits: one for each emf.
Step 3: The key requirement is that both circuits must have the same potential gradient. This means that the voltage change per unit length of the potentiometer wire must be the same for both circuits.
Step 4: If the potential gradients are the same, the readings from the potentiometer can be directly compared to determine which emf is greater or if they are equal.
Step 5: Ensure that the potentiometer is calibrated correctly before making the comparison.
Potential Gradient – The rate of change of potential difference per unit length along the potentiometer wire, which must be the same for both circuits to ensure accurate comparison of emfs.
Comparative Measurement – The process of using a potentiometer to measure and compare the electromotive forces (emfs) of two different sources.
