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The length of a given cylindrical wire is increased by 100% due to the consequent decrease in the diameter the change in the resistance of the wire will be

The length of a given cylindrical wire is increased by 100% due to the consequent decrease in the diameter the change in the resistance of the wire will be

Grade:11

2 Answers

Saurabh Koranglekar
askIITians Faculty 10335 Points
3 years ago
Dear student

Keeping volume const

If new length is 2l

New radius is r/(sqrt(2))

R = roh ( l/ area)

Rnew = 4 R

Regards
Arun
25757 Points
3 years ago
R = p L/A
New l` = 2l ..
Due to increase in length, area must decrease as volume remains constant..
Al = A`l` 
Hence, A` = A/2 
New Resistance R` = pl`/A` = 4pl/A
Change in resistance = 3pl/A or 300 %

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