Question

calcule a resistividade de um condutor de 220v, intensidade 30A comprimento de 80 metros

Answer 1

Ola

R= U/ i

R= 220 v / 30 A

R= 7,3

Agora usamos a 2ª Lei de Ohm para o condutor:

\large \mathsf{R=\rho\,\dfrac{L}{S}}\\\\\\ \mathsf{\rho=\dfrac{R\cdot S}{L}}\\\\\\ \mathsf{\rho=\dfrac{(10~\Omega)\cdot (5\cdot 10^{-7}~m^2)}{80~m}}\\\\\\ \mathsf{\rho=\dfrac{10\cdot 5\cdot 10^{-7}}{80}~\Omega\cdot m}\\\\\\ \mathsf{\rho=\dfrac{50\cdot 10^{-7}}{80}~\Omega\cdot m}\\\\\\

\large \boxed{\begin{array}{l}\mathsf{\rho=6,\!25\cdot 10^{-8}~\Omega\cdot m} \end{array}}\qquad\quad\checkmark

p= 6,25 . 10 . -8