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A resistance wire has a resistance R. Half of this wire is stretched to double its length and half is twisted to double the thickness, then its new resistance becomes1. 65R/32 2. 45R/323. 35R/324. 15R/32 |
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Answer» Correct option 1. 65R/32 Explanation: (I) Half length increased to doubled New length = l New area = A/2 R' = 2R ′ (II) Half length twisted to double the thickness New length l /4 New area = 2A R' = 1/8 R New resistance 2R + 1/8R = 17/8R |
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