Question

The electric field caused by charges in semiconductor devices can be an important factor in the operation of the device. Consider a situation where there are two line charges in a device (essentially microscopic wires), one charged positive and one charged negative, both of equal length L, as shown in the figure.

The magnitude of the charges on the rods are:

Q₁ = 1.48 x 10^-17 C and Q₂ = 1.78 x 10^-17 C

(This is about the same as the charge of 100 electrons.)

The length of the line charges is L = 9.13 x 10^-6 m and the distance between the lines is d = 3.89 x 10^-6 m.

What is the magnitude of the total electric field caused by these two line charges at a point half-way between them and equal distance from the ends of both lines?

Give your answer in N/C to at least three significant figures.

Answer 1

the charge densities are

electric field due to first line charge is

Here k is the electrostatic force constant, k = 8.99 x 10⁹

electric field due to second line charge is

the magnitude of the net electric field is