Question

how is resistance of a conductor directly proportional to the "square" of the area of the cross section?? shouldn't it be without the square??​

Answer 1

Answer:

resistance is inversely proportional to Area of cross-section

Explanation:

by experimental values we get that .

r= rho l/A

Answer 2

Answer:

If we doubled the cross section area then new resistance -

R* = R/4 ( where R* is new and R is old resistance )

Now we comes to the formula -

R = ρL/A or

R = ρL*L/A*L = ρL2 /V or

R = ρL*A/A*A = ρV/A2

( where R=resistance, ρ=resistivity, L=length, A=area, V=L*A=volume (which remains constant))

So we easily calculate the resistance from those formulas whatever the length or area increases or decreases.