Calculate the electric field (magnitude and direction) at the upper right corner of a square 1.22 m on a side if the other three corners are occupied by 2.40×10−6 C charges. Assume that the positive x-axis is directed to the right.

Respuesta :

Explanation:

It is mentioned that the magnitude of given charge is [tex]2.40 \times 10^{-6} C[/tex] and side of the square is 1.22 m.

Hence, we will calculate the electric field due to charge at point A as follows.

              [tex]E_{a} = k\frac{q}{r^{2}}[/tex]

                        = [tex]\frac{9 \times 10^{9} \times 2.4 \times 10^{-6}}{(1.22)^{2}}[/tex]

                       = [tex]14.512 \times 10^{3} N/C[/tex] (acts along y-axis)

Electric field at D due to the charge at C is as follows.

              [tex]E_{c} = k\frac{q}{r^{2}}[/tex]            

                        = [tex]\frac{9 \times 10^{9} \times 2.4 \times 10^{-6}}{(1.22)^{2}}[/tex]

                       = [tex]14.512 \times 10^{3} N/C[/tex] (acts along y-axis)

Electric field at D due to the charge at B is as follows.

         [tex]E_{d} = k\frac{q}{r^{2}}[/tex]            

                        = [tex]\frac{9 \times 10^{9} \times 2.4 \times 10^{-6}}{(1.7253)^{2}}[/tex]

                       = [tex]7.2564 \times 10^{3} N/C[/tex]

Now, we will resolve it into two components.

      [tex]E_{bx} = E_{b} Cos 45 = 5.1318 \times 10^{3} N/C[/tex]

      [tex]E_{by} = E_{b} Sin 45 = 5.1318 \times 10^{3} N/C[/tex]

Now, the resultant x component is as follows.

        [tex]E_{x} = (14.512 + 5.1318) \times 10^{3} = 19.6438 \times 10^{3} N/C[/tex]

Resultant y component is given as follows.

        [tex]E_{y} = (14.512 + 5.1318) \times 10^{3} = 19.6438 \times 10^{3} N/C[/tex]

Therefore, resultant electric field at point D is as follows.

       [tex]E = \sqrt{E^{2}_{x} + E^{2}_{y}}[/tex]

                  = [tex]\sqrt{(19.6438 \times 10^{3})^{2} + (19.6438 \times 10^{3})^{2}}[/tex]

                  = [tex]27.780 \times 10^{3} N/C[/tex]

And, the direction of electric field is

            [tex]\theta = tan^{-1} (\frac{E_{y}}{E_{x}})[/tex]

                        = [tex]tan^{-1} (1)[/tex]

                         = [tex]45^{o}[/tex]

This means that net electric field makes an angle of [tex]135^{o}[/tex] with positive x-axis in counter clockwise direction.