With the help of potentiometer, we can determine the value of emf of a given cell. The sensitivity of the potentiometer is
(A) directly proportional to the length of the potentiometer wire
(B) directly proportional to the potential gradient of the wire
(C) inversely proportional to the potential gradient of the wire
(D) inversely proportional to the length of the potentiometer wire
Choose the correct option for the above statements:
(A) directly proportional to the length of the potentiometer wire
(B) directly proportional to the potential gradient of the wire
(C) inversely proportional to the potential gradient of the wire
(D) inversely proportional to the length of the potentiometer wire
Choose the correct option for the above statements:
- (A)B and D only
- (B)A and C only✓ Correct
- (C)A only
- (D)C only
Answer: (B)
Solution
The sensitivity of a potentiometer measures how small a potential difference it can resolve, and this improves as the potential gradient along the wire is made smaller, so sensitivity is inversely proportional to the potential gradient. For a fixed potential drop, a longer wire spreads that drop over more length and so lowers the gradient, making sensitivity directly proportional to the length of the wire as well. Sensitivity is therefore directly proportional to the length and inversely proportional to the potential gradient.
JEE Main · 2023 · 29 Jan 2023 · Shift 2 · Single correct option