Question

A wire of given material having length l and area of cross section is a has a resistance of 4 ohm what would be the resistance of another wire of the same material having length l/2 and area of cross section is 2a qstn is from which book

Answer 1

since the material is same the resistivity is also same

we know that,

R is propotional to l/a

when length is halved (l/2) and area is doubled,

then

R' is proportional to 2l/2a = l/a

here

R=R'=4Ω