please solve this question

Asked by www1028 | 13th Jul, 2010, 09:32: PM

Expert Answer:

Given l1 = 1m.
l2 = 2m.
 
As the mass of the wire will remain constant and it is given that density remains constant that mean volume is also constant, therefore
 
l1xA1 = l2xA2
 
i.e., A2 = l1xA1/l2 = A1/2
 
Now we have, R1 = rxl1/A1                  where r = resistivity of the wire
 
and R2 = rxl2/A2
           = rx(2l1/(A1/2))
           = 4x(rxl1/A1)
           = 4R1

Answered by  | 15th Jul, 2010, 03:33: PM

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