Question

What is the resistance of the cube if its length is doubled?

Answer 1

resistance=∫l/a

here,resistance(R)=∫l/l*l=∫1/l

when length is doubled, then side=2l,area=2l*2l=4l²

∴ new resistance (r)=∫2l/4l²=∫1/2l=∫1/l*1/2=R/2

i.e the resistance becomes 1/2