Question

a wire is stretched to double its length, calculate % change in resistance

Answer 1

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R= p L/ A ------------------------------ ( a )

Now new R' after doubling the length 

R'= p2 L/ A ----------------------------------( b) 

R' = 2 p L/A 

Put the value of eq a into b 

R' = 2 R 
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Now percentage increase = $\frac{R'}{R}$ x 100 

                                          = $\frac{2R}{R}$ X100

                                          = 200 %  
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Answer 2

Explanation:

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