Question

resistivity of material of a wire is p. if area of cross section is doubled and length is halved, its resistivity will be​

Answer 1

The resistance of the wire related to length 'l' and area ‘A’ of the conductor is given by-

R=Pl/A whre P is the specific resistance of the conductor

Given l'= l/2  

A'= 2A  

Hence ,

R'=P(l/2)/2A

= P(l/A)*1/4

R'=1/4(R)

Hence the new resistance will be quarter the value or 1/4 of original resistance

Thank-you