Potentiometer

IMPORTANT

Potentiometer: Overview

This topic covers concepts, such as, Potentiometer, To Find EMF of an Unknown Battery Using Potentiometer, To Find Internal Resistance of an Unknown Battery Using Potentiometer & Conditions for No Balanced Point in Potentiometer etc.

Important Questions on Potentiometer

MEDIUM
IMPORTANT

Balancing point of a potentiometer shifts from a length of 60 cm to 40 cm by shunting the cell with a 4 Ω resistance. What is the internal resistance of the cell?

EASY
IMPORTANT

A cell of 2V, 1Ω is balanced at 1.9 m. Then what is balanced length for ideal cell of 2V ?

MEDIUM
IMPORTANT

 In the following figure, the p.d. between the points M and N is balanced against 50 cm length of potentiometer wire of total length 100 cm. In order to balance the potential difference between the points N and C the jockey to be pressed on potentiometer wire at a distance of in cm:

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EASY
IMPORTANT

The potential gradient of potentiometer is 0.2 volt m-1. A current of 0.1 amp is flowing through a coil of 2 Ohm resistance. The balancing length in meters for the p.d. at the ends of this coil will be

EASY
IMPORTANT

The length of a wire of a potentiometer is 100 cm, and the emf of its standard cell is E volt. It is employed to measure the emf of a battery whose internal resistance is 0.5 Ohm. If the balance point is

EASY
IMPORTANT

Resistivity of potentiometer wire is 10-7Ωm and its area of cross-section is 10-6 m2. When a current i=0.1 A flows through the wire, its potential gradient is :

EASY
IMPORTANT

When a cell is balanced on potentiometer wire, then balancing length is 125 cm. If resistance of 2 ohm is connected across the ends of cell, then balancing length is 100 cm, then internal resistance of cell is

EASY
IMPORTANT

A cell is balanced at 100 cm of a potentiometer wire when the total length of the wire is 400 cm. If the length of the potentiometer wire is increased by 100 cm, then the new balancing length for the cell will be (Assume pd across potentiometer wire is constant)

EASY
IMPORTANT

Figure shows a 2.0 V potentiometer used for the determination of internal resistance of a 1.5 V cell. The balance point of the cell in open circuit is 76.3 cm. When a resistor of 9.5 Ω is used in the external circuit of the cell, the balance point shifts to 64.8 cm length of the potentiometer wire. Fine the internal resistance of the cell (in Ω) correct to the nearest integer.

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EASY
IMPORTANT

One of the circuits for the measurement of resistance by potentiometer is shown. The galvanometer is connected at point A and zero deflection is observed at length PJ=30 cm. In second case the secondary cell is changed and zero deflection is observed at length PJ=10 cm. What is the resistance R (in ohm) ? Take ES=10 V and r=1 Ω in 1st reading and ES=5 V and r=2 Ω in 2nd reading :

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EASY
IMPORTANT

A cell of internal resistance of 1 Ω and emf 5 V balances on a potentiometer wire at length of 2 m. The driving battery has emf of 50 V. If the cell is shunted by 1 Ω resistance wire then find by what amount balance point will shift?

HARD
IMPORTANT

The figure shows a potentiometer arrangement used to measure the internal resistance of the cell B. The null point Q is located at 20 cm from point P on a 100 cm wire PR. Find the internal resistance of the cell B.

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MEDIUM
IMPORTANT

In a potentiometer experiment when terminals of the cell are connected at distance of 52 cm on the wire, then no current flows through it. When 5 Ω shunt resistance is connected across the cell the balancing length is 40 cm. The internal resistance of the cell (in Ω) is n2 what is the value of n?

HARD
IMPORTANT

A wire AB (of length 1 m, area of cross-section π m2) is used in the potentiometer experiment to calculate the emf and internal resistance r of the battery. The emf and internal resistance of the driving battery are 15 V and 3 Ω respectively. The resistivity of wire AB varies as ρ=ρ0x, where x is distance from A in meters and ρ0=24π Ω. The distance of null point from A is obtained at 23 m when switch S is open. Find the value of E.

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HARD
IMPORTANT

A 10 m long potentiometer wire has a resistance of 20 ohm. It is connected in series with a battery of emf 3 V and a resistance of 10 Ω. The internal resistance of cell is negligible. If the length can be read accurately up to 1 mm, the potentiometer can read voltage with an accuracy of k10 (in millivolt). Then the value of k is

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HARD
IMPORTANT

A wire AB (of length 1 m, area of cross-section π m2) is used in potentiometer experiment to calculate emf and internal resistance r of battery. The emf and internal resistance of driving battery are 15 V and 3 Ω, respectively. The resistivity of wire AB varies as ρ=ρ0x, where x is distance from A in meters and ρ0=24π Ω-m. The distance of null point from A is obtained at 23 m when switch S is open. Find the value of E.

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EASY
IMPORTANT

In a potentiometer, find the value of EMF of a cell in V if the balancing length for this cell is 65 cm. Given that a cell of emf 1.5 V gave a balanced point at 32 cm length of the wire.

MEDIUM
IMPORTANT

If the specific resistance of a potentiometer wire is 10-7 Ω m, the current flowing through it is 0.1 A and the cross-sectional area of the wire is 10-6 m2 then, the potential gradient will be

EASY
IMPORTANT

A standard cell of 1.08 V is balanced by the PD across 90 cm of a meter long wire supplied by a cell of emf 2 V through a series resistor of resistance 2 Ω. If the internal resistance of the cell in the primary circuit is zero then the resistance per unit length of potentiometer wire is

HARD
IMPORTANT

The balancing length for a cell is 560 cm in a potentiometer experiment. When an external resistance of 10 Ω is connected in parallel to the cell, the balancing length changes by 60 cm. If the internal resistance of the ceil is N10Ω, where N is an integer then value of N is ............