Understanding Point Charges: Same Sign, Different Magnitudes?

In summary, the question is whether three point charges at the corners of a square have the same sign or same magnitude but different signs. The answer is that they would have the same sign and different magnitudes because the sign of the charge is not taken into account when calculating net electric fields. The diagonally opposite corner must have a different type of charge, and the negative sign changes the direction of the electric field.
  • #1
smunger81
12
0
Please Help!

I would really appreciate some help on this one...I'm pretty sure I'm making it harder than it is...

The question is this - "Three point charges are fixed to the corners of a square, one to a corner, in such a way that the net electric field at the empty corner is zero. Do these charges all have the same sign or the same magnitude but perhaps different signs?"

My answer is the charges would have the same sign and different magnitudes because when calculating net electric fields the sign of the charge is not taken into account...is this right?

Any advice would be fabulous! Thank you!
 
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  • #2
Sorry,
Let the empty corner is the origin and the three other points are (0, -a) (-a, 0) and (-a,-a). If all charges are having same sign (say +) then the forces are along y, x and bisector of x and y respectively. hence the charges must have different sign.

Actually the diagonally opposite corner must have one type of charge and the others have opposite type of charges.

Negative sign of the charge changes the direction of electric field which is a vector quantity.
 
  • #3
Thank you for your help. I was making it waay to hard.
 

1. What is a point charge?

A point charge is a hypothetical concept used in physics to represent a particle with a charge that is concentrated at a single point in space. It is often used in simplified models to study the behavior of electric charges.

2. How is the electric field of a point charge calculated?

The electric field of a point charge can be calculated using Coulomb's law, which states that the electric field strength at a point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance from the charge.

3. What is the difference between a point charge and a distributed charge?

A point charge is a single charge concentrated at a single point, while a distributed charge is a charge that is spread out over a larger area or volume. Point charges are often used in simplified models, while distributed charges are used in more complex systems.

4. Can a point charge exist in nature?

While point charges are used in theoretical models, it is not possible for a charge to be concentrated at a single point in physical space. This is because as charges get closer together, the electric field becomes infinitely strong, which is not physically possible.

5. How do point charges interact with each other?

Point charges interact with each other through the electric force, which can either attract or repel depending on the sign of the charges. The strength of the force is determined by the distance between the charges and the magnitude of their charges.

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