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A wire OF 3 OHMS resistance AND 10 cm length is stretched to 30 cm length assuming that it has uniform area of cross section what will be the new resistance. |
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Answer» The wire's volume stays the same, so the new cross-sectional AREA is 1/3 the ORIGINAL. Resistance is directly proportional to wire LENGTH and INVERSELY proportional to the cross-sectional area. Thus, by tripling the length and reducing the cross-sectional area to 1/3 the original, the resistance is now 9 times the original, or 27 OHMS. |
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