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Using Gauss’ law, find the approximate magnitude of the electric field at the surface of a cube that has 0.10-m sides and a uniform volume charge density ρ= 2.0 ×10−9C/m3.

How to solve it?

Respuesta :

Answer:

The approximate magnitude of the electric field at the surface of the cube is 1.8 N/C.

Explanation:

The electric field, E, at the surface of the cube can be determined by:

                  E =[tex]\frac{kq}{r^{2} }[/tex]

Where k is a constant (8.99 x 109 [tex]Nm^{2} C^{-2}[/tex]), q is the charge and r the distance from the charge.

But the volume charge density, ρ, is given as:

                 ρ = [tex]\frac{q}{V}[/tex]

where: q is the electric charge and V the volume.

From the question, sides of cube = 0.10 m and uniform volume charge density, ρ = 2.0 × [tex]10^{-9}[/tex][tex]Cm^{-3}[/tex].

Thus:

volume of cube = length ×length × length

                          = 0.10 ×0.10 ×0.10

                          = 1.0 × [tex]10^{-3}[/tex] [tex]m^{3}[/tex]

So that:

            q = ρ × V

               = 2.0 × [tex]10^{-9}[/tex] × 1.0 × [tex]10^{-3}[/tex]

               = 2.0 × [tex]10^{-12}[/tex]

            q = 2.0 × [tex]10^{-12}[/tex] C

The electric field, E, at the surface of the cube can be determined by:

                  E =[tex]\frac{kq}{r^{2} }[/tex]

k = 8.99 x 109 [tex]Nm^{2} C^{-2}[/tex]), q = 2.0 × [tex]10^{-12}[/tex] C, r = 0.1 m, so that:

                E = [tex]\frac{8.99*10^{9} * 2*10^{-12} }{0.1^{2} }[/tex]

                   = 1.798 N/C

The approximate magnitude of the electric field at the surface of the cube is 1.8 N/C.