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Lengths and cross-sectional areas of thr...

Lengths and cross-sectional areas of three copper wires are (l, A ), `(2l, (A)/(2) ) , ((l)/(2) , 2A ) `. Which of these wires has least (minimum) resistance ?

A

Second wire

B

First wire

C

Third wire

D

All the wires have same resistance

Text Solution

Verified by Experts

The correct Answer is:
C
Third wire
Because resistance of wire,
(i) R `alpha l (ii) R alpha (1)/(A)`
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KUMAR PRAKASHAN-CURRENT ELECTRICITY-SECTION [D] MULTIPLE CHOICE QUESTIONS (MCQs) (MCQs FROM .DARPAN. BASED ON TEXTBOOK)
  1. When an electric cell is in use, .... Relation holds good.

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  2. Resistivity of material does not depend on ...... of conductor

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  3. Lengths and cross-sectional areas of three copper wires are (l, A ), (...

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  4. Which of the following curve represents negative resistance ?

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  5. ..... is Ohm 's law for good conductor

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  6. Ohmic resistance of conductor .....

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  7. SI unit of electrical conductivity is

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  8. For a block with dlmensions 1 cm xx 1 cm xx 100 cm havng resistivity...

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  9. Specific resistance of material of one wire is rho. Its volume is 3 m^...

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  10. Which is the dimensional formula for conductance from the given below ...

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  11. The physical quantity having the dimentiom, M^(-1) L^(-3) T^(3) A^(2) ...

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  12. SI unit of electrical conductivity is

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  13. Resistance of wire having diameter 2 mm and length 100 cm is 0.7 Omega...

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  14. Resistance of wire having radius r is R. If new wire of radius 2r, is ...

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  15. On applying an electric field of 15 xx 10^(-6) vm^(-1) across a cond...

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  16. The ratio of length of two wires of same mass arc made up of same mate...

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  17. Resistance of a wire is ROmega. It is stretched uniformly till Its len...

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  18. J = sigma E represents ........ .

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  19. On increasing the temperature of a conductor the product of its resist...

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  20. When the temperature of a conductor increase the ratio of its resistiv...

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