A potentiometer circuit is set up as shown. The potential gradient… | NEET 2010 (AIPMT, Prelims)

Q83NEET 2010 · AIPMT · PRELIMSMedium

Potentiometer

A potentiometer circuit is set up as shown. The potential gradient, across the potentiometer wire, is k volt/cm and the ammeter, present in the circuit, reads 1.0 A when two way key is switched off. The balance points, when the key between the terminals (i) 1 and 2 (ii) 1 and 3, is plugged in, are found to be at length $l$ 1 cm and $l$ 2 cm respectively. The magnitudes, of the resistors R and X, in ohms, are then, equal, respectively, to

Show answer and solution

Answer: (b)

Current through R and X is $I = 1.0\ \text{A}$ .
Key 1–2: galvanometer balances p.d. across R: $IR = k l_1 \Rightarrow R = k l_1$ .
Key 1–3: it balances p.d. across R + X: $I(R + X) = k l_2 \Rightarrow X = k(l_2 - l_1)$ .
So the answer is (b) $k l_1$ and $k(l_2 - l_1)$ .

Report a mistake

Potentiometer question from NEET 2010 (AIPMT, Prelims)

More questions on Potentiometer