Consider a long cylindrical charge distribution of radius R = 17 cm with a uniform charge density of rho = 15 C/m3. Find the electric field at a distance r = 26 cm from the axis.

Respuesta :

Answer:

[tex]E = 9.4*10^{10}N/C[/tex]

Explanation:

We use Gauss's law which says

[tex]$\int E\cdot dA = \frac{Q_{enc}}{\varepsilon}. $[/tex]     [tex](1)[/tex]

Now, for the cylindrical charge distribution the charge enclosed is

[tex]Q_{enc} = \rho V[/tex]

where [tex]V[/tex] is the volume of the cylinder.

To evaluate Gauss's law, the Gaussian surface we choose is a cylinder concentric with the charged cylinder; therefore, equation  [tex](1)[/tex] becomes

[tex]E (2\pi rL )=\dfrac{\rho V}{\varepsilon _o}[/tex]

[tex]E (2\pi rL )=\dfrac{\rho \pi R^2L}{\varepsilon _o}[/tex]

[tex]E =\dfrac{\rho \pi R^2L}{ (2\pi rL )\varepsilon _o }[/tex]

[tex]\boxed{E =\dfrac{\rho R^2}{ 2\varepsilon _o r }}[/tex]

Putting in numerical values

[tex]\rho = 15C/m^3[/tex]

[tex]R = 17cm =0.17m[/tex]

[tex]r = 26cm=0.26m[/tex]

[tex]\varepsilon_0 =8.85*10^{-12}m^{-3}kg^{-1}s^4A^2}[/tex]

we get:

[tex]E =\dfrac{15 (0.17)^2}{ 2(8.85*10^{-12}) (0.26) }[/tex]

[tex]\boxed{E = 9.4*10^{10}N/C}[/tex]

Otras preguntas