Ans 14
Q.14. A piece of wire is redrawn by pulling it until its length is doubled. Compare the new resistance with the original value?
Dear student,The Resistance R=ρl/A where l= length of the wire A= Area of crossection of wireSince, the length of the wire is doubled so, l'=2lSince, for a change in conductor the mass And density remains intact and area changes in the equal inverse proportionSo, area A'=A/2R'=ρl'/A'R'=ρ2l/A/2R'=4ρl/AR'=4RSo, the new resistance will be equal to the four times of the original resistance.Regards