A wire of length l, area A is made in to a wire of double its length by -

Asked by akshitajain | 4th Feb, 2010, 08:31: PM

Expert Answer:

Dear Student

Resistivity is a material constant , it wont changes with L or A.

R= p L/A        p= resistivity, L =length, R=resistance

now let us see the cases 1, 2

(I) attaching a similar wire.

This is like 2 resistences in series  ==> resistance will be doubled

(ii) Melting the existing wire

So area of cross section will be A/2, Length=2L  ==>  Resistance= p 2L/(a/2)  =4p L/A  = 4 times the initial resistance



Topper leraning

Answered by  | 5th Feb, 2010, 11:11: AM

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