Home
Class 12
PHYSICS
A potentiometer wire has length 4m and r...

A potentiometer wire has length 4m and resistance `8Omega` the resistance that must be connected in series with the wire and an accumulaterof emf 2 V so as to get a potential gradient 1 mV ,per cm on the wire is

A

`32Omega`

B

`40Omega`

C

`44Omega`

D

`48Omega`

Text Solution

Verified by Experts

The correct Answer is:
A
Resistance of the potentimeter wire of lengh 1cm
`(8Omega)/(400"cm")=(1)/(50)Omega//"cm"`
If the potential differnce at the two ends of 1 cm portion `1mV" or " 10^(-3)V,`
then the current through the wire , `I=(10^(-3))/((1)/(50))=(1)/(20)A`
For the entire circuit , `I=(E)/(R_(P)+R)`
`"or, "R=(E)/(I)-R_(P)=(2)/((1)/(20))-8=32Omega`
Promotional Banner

Topper's Solved these Questions

  • KIRCHHOFF'S LAWS AND ELECTRICAL MEASUREMENT

    CHHAYA PUBLICATION|Exercise EXAMINATION ARCHIVE (NEET)|1 Videos

  • KIRCHHOFF'S LAWS AND ELECTRICAL MEASUREMENT

    CHHAYA PUBLICATION|Exercise CBSE SCANNER|16 Videos

  • KIRCHHOFF'S LAWS AND ELECTRICAL MEASUREMENT

    CHHAYA PUBLICATION|Exercise EXAMINATION ARCHIVE (JEE Main)|6 Videos

  • ELEMENTARY PHENOMENA OF ELECTROSTATICS

    CHHAYA PUBLICATION|Exercise EXAMINATION ARCHIVE|2 Videos

  • LIGHT WAVE AND INTERFERENCE OF LIGHT

    CHHAYA PUBLICATION|Exercise CBSE SCANNER|15 Videos

Similar Questions

Explore conceptually related problems

A potentiometer has 10 wires each of 1 meter length and the total resistance is 20Omega . Find the resistance to be connected to the driving battery of emf 2 volts to produce a potential drop of 1 mu V per millimeter.

A Potentiometer has 10 wires each of 1 metre length and the total resistance is 20 Omega . Find the resistance to be connected to the driving battery of emf 2 volts to produce a potential drop of 1 muV per millimetre. (Graph sheet is not required).

A potentiometer wire of length 100 cm has a resistance of 10Omega . It is connected in series with a resistance and a cell of emf 2V and of negligible internal resistance. A source of emf 10 mV is balanced against a length of 40 cm of the potentiometer wire. What is the value of external resistance ?

A potentiometer wire has a length 10m and a resistance of 4 ohm. A cell of emf 2V and a resistance box are connected in series with it. Calculate the resistance to be introduced in the box, so as to get a potential gradient of 0.1Vm^-1 .

The resistance of a potentiometer wire of length 10m is 20 ohm. A resistance box and a 2 volt accumulator are connected series with it. Resistance required to be introduced in the box to have a potential drop of one microvolt per millimeter of the potentiometer wire will be

A potentiometer of 20 Omega has 10 wires each of 1 metre length and the total resistance to be connected to the driving battery of emf 2 volts to produce a potential drop of 1muV per millimetre . (Graph sheet is not required ) .

A cell of emf 2Vand internal resistance 1.5Omega is connected to two ends of 100 cm wire. The resistance of the wire is 0.005 Omega//cm. The potential gradient of the wire is

In the following circuit fig, a 10m long potentiometer wire with resistance 1,2 ohm/m, a resistance R_1 and an accumulator of e.m.f. 2V are connected in series. When the e.m.f. of thermocouple is 2.4 mV the deflection in galvanometer is zero. The current supplied by the accumulator will be