Question

Problema 2.22 , va rog sa ma ajutati din tot sufletul ^_^ . Pls!! Thx... Dau coroana!!!! ^_^

Answer 1

[tex]\tt Se~da:\\ \\ \rho_{1}=28,2n\Omega\times m=2,82 \times 10^{-8}\Omega\times m\\ \\ l_{1}=2,5m\\ \\ a=1cm=0,01m\\ \\ b=5cm=0,05m\\ \\ \rho_{2}=98n\Omega\times m=9,8 \times 10^{-8}\Omega\times m\\ \\ d=15mm=0,015m\\ \\ R_{1}=R_{2}\\ \\ a)R_{1}=?\Omega\\ \\ b)l_{2}=?m\\ \\ \\[/tex]


[tex]\tt Formule:\\ \\ a)R_{1}=\rho_{1} \times \frac{l_{1}}{S_{1}}\\ \\ R_{1}=\rho_{1} \times \frac{l_{1}}{a\times b}\\ \\ \\ b)R_{2}=R_{1}\\ \\ R_{1}=\rho_{2}\times\frac{l_{2}}{S_{2}}\\ \\ \\ S_{2}=\pi\times R^{2} \\ \\ S_{2}=\pi\times\frac{D^{2}}{4}\\ \\ \\ R_{1}=\rho_{2}\times\frac{l_{2}}{\pi\times\frac{D^{2}}{4}}\\ \\ R_{1}=\rho_{2}\times\frac{4 \times l_{2}}{\pi\times D^{2}}\\ \\ l_{2}=\frac{R_{1}\times \pi \times D^{2}}{4\times\rho_{2}}\\ \\ \\[/tex]



[tex]\tt Calcule: \\ \\ a)R_{1}=2,82 \times 10^{-8} \times \frac{2,5}{0,01\times 0,05}=14100\times 10^{-8} \Omega\\ \\ \\ b)l_{2}=\frac{14100\times 10^{-8}\times 3,14 \times 0,015^{2}}{4\times 9,8 \times 10^{-8}}\approx 0,255m\\ \\[/tex]