A tube of mercury with resistivity 9.84 × 10 -7 Ω ∙ m has an electric field inside the column of mercury of magnitude 23 N/C that is directed along the length of the tube. How much current is flowing through this tube if its diameter is 1.0 mm?

Respuesta :

Answer:

The current through the tube is 73.39A.

Explanation:

The relationship between the resistivity [tex]\rho[/tex], the electric field [tex]E[/tex], and the current density [tex]J[/tex] is given by

[tex]\rho = \dfrac{E}{J}[/tex]

This equation can be solved for [tex]J[/tex] to get:

[tex]J = \dfrac{E}{\rho}[/tex]

Since the current is [tex]I = J\cdot A[/tex]

[tex]I= J\cdot A = \dfrac{E}{\rho} \cdot A[/tex]

Now, for the tube of mercury [tex]\rho = 9.84*10^{-7}\: \Omega \cdot m[/tex], [tex]E = 23N/C[/tex], and the area is [tex]A = \pi r^2 = \pi (1.0*10^{-3}m)^2 = 3.14*10^{-6}m^2[/tex]; therefore,

[tex]I= \dfrac{23N/C}{9.84*10^{-7}\Omega\cdot m } *3.14*10^{-6}m^2[/tex]

[tex]\boxed{I = 73.39A.}[/tex]

Hence, the current through the mercury tube is 73.39A.