3 cylindrical copper conductors having length L , 2L and L/2 respectively have their face areas A, A/2 and 2A - Physics - Electricity

Question

3 cylindrical copper conductors having length L , 2L and L/2
respectively have their face areas A, A/2 and 2A respectively are
given Which of the conductors willhave the highest resistance and
why? Compare their resistivity

Rohit Babu · Accepted Answer

Dear Student,We know,Resistance,R=ρlAρ→Resistivity of the material
A→Area of cross section of the conductor
l→Length of the conductor
For the first copper conductor, resistance is:R1=ρLA 
1For the second copper conductor, resistance is:R2=ρ2LA2 =2×2ρLA=4ρLA
2For the third  copper conductor, resistance is:R3=ρL22A =ρL2×2A=14×ρLA
3Second conductor will have the highest resistance
Because it has the largest lengthand smallest area of cross section
Resistivity is a property of the material of the conductor
 It is not affected by the length or area of the conductor
Since all the three conductors are made of copper,their resistivity will be the same
Regards

3 cylindrical copper conductors having length L , 2L and L/2 respectively have their face areas A, A/2 and 2A respectively are given. Which of the conductors willhave the highest resistance and why? Compare their resistivity.