Why does the point experience NEGATIVE field strength?

In summary, the question is asking why the electric field strength at a certain point experiences a negative value when it is closer to a positive source, or vice versa. The answer explains that at a point where the resultant electric field strength is zero, the sign indicates the direction of the field. In this case, being on different sides of the charges A and B results in a different direction and therefore a different sign. The significance of this for the question is also emphasized.
  • #1
1832vin
58
1
Hi, i'm looking for an explanation to this answer of a past paper that I'm doing, it's from OCR (A level) G485, question 1 b ii)

the question on top, and answer on bottom

upload_2016-5-28_22-46-32.png


i don't understand why would the point experience a negative electric field strength when it's getting closer to a positive source or vice versa (positive field strength) , this is the first question of the paper, and not much other relevant information is presented... what am i not understanding?

http://www.ocr.org.uk/Images/243747-question-paper-unit-g485-01-fields-particles-and-frontiers-of-physics.pdf [Broken]

thankyou
 
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  • #2
At point X , the magnitude of the resultant electric field strength due to the particles A and B is zero
That is an important part of the question.

The sign gives the direction. If you are close to one of the charges, the influence of this charge dominates, but to the left of X you are on the right side of the charge A, to the right of X you are on the left side of charge B. The direction towards the charge is different, and a different direction means a different sign.
 
  • #3
i didn't notice! thanks

i even drew out the diagrams and i still didn't caught that, thanks
 

1. Why does the point experience NEGATIVE field strength?

The point experiences negative field strength because it is located in a region where the electric field lines are directed towards it. This means that the electric field is pulling negative charges towards the point, resulting in a negative field strength.

2. What factors contribute to negative field strength at a point?

The negative field strength at a point is influenced by the presence of nearby charged particles, the distance between the point and these particles, and the strength of their charges. The direction of the electric field lines also plays a role in determining the sign of the field strength.

3. Can a point experience both positive and negative field strength?

Yes, a point can experience both positive and negative field strength depending on its location and the surrounding charged particles. If the point is located in a region where there are both positively and negatively charged particles, it will experience both positive and negative field strength at different points.

4. How is negative field strength measured?

Negative field strength is measured in units of force per unit charge, also known as volts per meter (V/m). This unit describes the strength of the electric field at a point and indicates the direction of the field lines. The higher the negative field strength, the greater the force exerted on negative charges at that point.

5. What are the practical applications of negative field strength?

Negative field strength plays a crucial role in various applications, such as electronics, telecommunications, and medical devices. For example, negative field strength is used in electronic devices to control the flow of electrons and in medical devices to stimulate nerve and muscle activity. It also helps in understanding the behavior of charged particles in electric fields, which is important in fields like particle physics and astronomy.

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