Question #6f780

1 Answer
Jan 19, 2018

Answer:

#"please have a look at the fallowing details. (option c)"#

Explanation:

1- In order to understand the solution, we need to remember the following important points.

  • An electric field is formed around the electric charges.
  • Electric field is a vectorial quantity.
  • The direction of the electric field generated by the electric charge with positive sign is directed outward from the charge.

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  • The direction of the electric field generated by the electric charge in the negative sign is directed from the outside to the charge.

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  • We calculate the electric field intensity at a point far from an electric charge by using the following formula...

#E=k*q/r^2#

  • The growth of r (away from load) causes the intensity of the electric field to decrease.

  • In the given diagram space is colored by dividing into three regions.

  • Two vectors representing the electric field in each region are drawn.
  • Note the directions of the vectors in the regions.

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  • The point we are looking for can not be in the yellow zone (because the vectors are in the same direction).

  • In order for the electric field to be zero, the magnitudes of the vectors must be equal and opposite.

  • Which of the green or blue regions may be zero? we need to answer the question.

  • To make it easier to understand, let's take the distance between points equally (indicated by x).

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  1. Now we can solve the problem.

  2. Let's calculate the electric field at point K.

#vec E_K=k*(+q)/x^2+k*(-3q)/(2x)^2=(kq)/x^2-(3kq)/(4x^2)#

  • Let's calculate the electric field at point R.

#vec E_R=k*(+q)/(4x)^2+k*(-3q)/(x)^2=(k q)/(16x^2)-(3kq)/x^2#

  • Electric field intensity is proportional to the magnitude of the load and is inversely proportional to the distance.

#(3kq)/x^2>(k q)/(16x^2)#

  • The point we're looking for is not in the blue zone.

  • The intensity of the electric field can be zero in the green-painted space zone.