Potentiometer has multiple uses. It is based on the principle that when constant current flows through a wire of uniform area of cross-section then potential drop along its length is directly proportional to corresponding length.
i.e. $V \propto I$
$V=K I$
Various uses of potentiometer on:
- To measure potential differences between any two points in an electrical network
- To compare emf of a cell
- To measure emf of a cell
- To measure internal resistance of a cell etc.
Answer the following question related to potentiometer:
What happens to the balancing length when resistance S is increased?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Balancing length increases
Terminal potential difference across battery, = $E – ir$
⇒ $E-\frac{E}{S+r} . r$
Now as the value of S is increased, terminal potential difference increases hence balancing length increases.