A straight nonconducting plastic wire 9.5 cm long carries a charge density of 100 nc/m distributed uniformly along its length. It is lying on a horizontal tabletop. A. Find the magnitude and direction of the electric field this wire produces at a point 4.50 cm directly above its midpoint. B. If the wire is now bent into a circle lying flat on the table, find the magnitude and direction of the electric field it produces at a point 4.50 cm directly above its center.

Respuesta :

Answer:

Explanation:

Given that,

Length of wire = 9.5 cm =

Charge density = 100 NC/m

Distance = 4.50 cm

(A). We need to calculate the  the magnitude and direction of the electric field

Using formula of magnetic field

[tex]E=\dfrac{k\lambda\times l}{x\sqrt{x^2+a^2}}[/tex]

Here, x = distance from mid point of the wire

Put the value into the formula

[tex]E=\dfrac{9\times10^{9}\times100\times10^{-9}\times9.5\times10^{-2}}{4.50\times10^{-2}\sqrt{(4.50)^2+(\dfrac{9.5\times10^{-2}}{2})^2}}[/tex]

[tex]E=2.90\times10^{4}\ N/C[/tex]

The electric field is [tex]2.90\times10^{4}\ N/C[/tex].

The direction of electric field is upward.

(B). If the wire is now bent into a circle lying flat on the table,

We need to calculate the the magnitude and direction of the electric field

Using formula of electric field

[tex]E=\dfrac{k\lambda lx}{(x^2+(\dfrac{L}{\2\pi})^2)^{\dfrac{3}{2}}}[/tex]

Put the value into the formula

[tex]E=\dfrac{9\times10^{9}\times100\times10^{-9}\times9.5\times10^{-2}\times4.50\times10^{-2}}{((4.50\times10^{-2})^2+(\dfrac{9.5\times10^{-2}}{2\pi})^2)^{\dfrac{3}{2}}}[/tex]

[tex]E=3.59\times10^{4}\ N/C[/tex]

The electric field is [tex]3.59\times10^{4}\ N/C[/tex]

The direction of electric field is upward.

Hence, This is the required solution.