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If a wire of resistance R is melted and recast to half of its length,What is the new resistance of wire is get? |
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Answer» Explanation:Your answer is ---Let, length of wire is l and area of cross section is A .Given, it's resistance is RSO, r = rho l/A .....(1)SINCE, wire is MELTED and recast to HALF its length .so, it's area of cross become doublesuch that , new length l' = l/2 and new area of cross section is A' = 2Atherefore , new resistance R isR = rho l'/A'=> R = rho l/2/2A=> R = 1/4 × rho l/A=> R = 1/4r (from 1)hence, new resistance is 1/4 r================Hope it helps you============== |
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