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A potentiometer wire of length 100 cm ha...

A potentiometer wire of length `100 cm` having a resistance of `10 Omega` is connected in series with a resistance `R` and a cell of emf `2V` of negligible internal resistance. A source of emf

of `10 mV` is balanced against a length of `40 cm` of the potentiometer wire. What is the value of resistance `R` ?

A

`790 Omega`

B

`890 Omega`

C

`990 Omega`

D

`1090 Omega`

Text Solution

Verified by Experts

The correct Answer is:
A
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NCERT FINGERTIPS-PRACTICE PAPPER-Practice Paper 3
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  3. A thin metal plate P is inserted between the plates of a parallel-plat...

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  4. A positively charged thin metal ring of radius R is fixed in the xy pl...

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  5. A voltmeter having a resistance of 1800 Omega employed to measure the ...

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  6. A microammeter has as resistance of 100 Omega and full scale range of ...

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  7. A 100 W bulb B(1) and two 60 W bulbs B(2) and B(3), are connected to a...

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  8. A short conducting rod P of length 3.0 cm is placed parallel to an nea...

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  9. A rectangular loop carrying a current i is situated near a long strai...

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  10. An electron and a proton enter a magnetic field at right angles to the...

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  11. A gang capacitor is formed by interlocking a number of plates as shown...

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  12. A galvanometer of resistance 25Omega is connected to a battery of 2 vo...

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  13. A rectangular coil of 20 turns and area of cross-section 25 cm^(2) has...

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  14. For perfectly coupled coils, the coupling coefficient should be equal ...

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  15. A 200 muF capacitor in series with a 100 Omega resistance is connected...

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  16. The efficiency of a transformer is 90%. The transformer is rated for o...

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  17. In an experiment to find focal length of a concave mirror, a graph is ...

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  18. In a reflecting astronomical telescope, if the objetcive (a spherical ...

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  19. Which one of the following is a possible nuclear reaction ?

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  20. A 5 W source emits monochromatic light of wavelength 5000 Å. When plac...

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  21. Calculate in how many months , (3/4)^(th) of the substance will dacay,...

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