In a circuit two resistances of the same material and cross section area but different lengths L1 and L2 are kept in series. Find the length of the equivalent resistance if it's made of the same material and same cross section area.
L1 +L2
Resistance of both the resistance will be R1=ρL1A and R2=ρL2A
Since they are in series so R net R net=ρLnetA=R1+R2=p(L1+L2)A
So Lnet=L1+L2