Question

length of wire is made four times and area is doubled then new resistance is.......?

Answer 1

R = ρ. (l/A)              l=length

                              A=area of cross section

                               ρ=specific resistance

new resistance = ρ(4l/2A)

                          =ρ(l/A) X 2

                           =2R

    Therefore, new resistance=double of original resistance