Electricity and Magnetism

In summary: Q) + (Q+Q+Q) = 90 deg?In summary, the electrostatic potential of the center of a square is 4(9*10^9)(Q/(root2)s/2)? and the magnitude of electric field at the center of the same square is 9*10^9)(-Q/(root2)s/2) + (9*10^9)(-Q/(root2)s/2) - (9*10^9)(Q/(root2)s/2)?
  • #1
soccerjayl
53
0
I have a huge problem to work out..

but first, i can't find the equations for

(1) electrostatic potential of the center of a square (a charged particle at each vertice)

and

(2) the magnitude of electric field at the center of the same square.

These are both questions to two arrangements, one with positive and negative particles at opposite ends, and arrangement 2 with both negative on right vertices and both positive on left vertices..

thanks
 
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  • #2
Figure it out for yourself. It's not so hard:
(1) The potential at a distance r from a point charge is [itex]kq/r[/itex]. It's a scalar, so just add up the contributions from each charge.
(2) The field at a distance r from a point charge is [itex]kq/r^2[/itex]. This is a vector directed radially outward (from a positive charge). Add up the contributions from each charge (but remember they are vectors).
 
  • #3
so let me get this straight...sorry if this isn't a hard question to you, but we are just learning this..

for (1) in the situation where positives are at opposite vertices as well as negatives are at opposite vertices...the equation would be 4(9*10^9)(Q/(root2)s/2)? (with side s and charge +/-Q

for (2) in the same situation..it would be (9*10^9)(-Q/(root2)s/2) + (9*10^9)(-Q/(root2)s/2) - (9*10^9)(Q/(root2)s/2) - (9*10^9)(Q/(root2)s/2)?
 
Last edited:
  • #4
soccerjayl said:
so let me get this straight...sorry if this isn't a hard question to you, but we are just learning this..

for (1) in the situation where positives are at opposite vertices as well as negatives are at opposite vertices...the equation would be 4(9*10^9)(Q/(root2)s/2)? (with side s and charge +/-Q

for (2) in the same situation..it would be (9*10^9)(-Q/(root2)s/2) - (9*10^9)(-Q/(root2)s/2) + (9*10^9)(Q/(root2)s/2) - (9*10^9)(Q/(root2)s/2)?

For (2) u can't add the contributions as if they were scalars.U have to add vectors.Make the correct picture in which draw every force.Project every force upon 2 perpendicular axes (parallel with the sides of the square) and add algebraically the projections which can be taken as scalars.
Geometry in electrostatics is essential.U should be getting factors with sine and cosine of pi/4.
 
  • #5
i know this is aggravating for you, but how would u add up 4 vectors? Do you mean make 4 triangles with the square and make the forces on one axis and add/subtract?

(and are the -Q's going toward P with the +Q's going away from P?)
 
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  • #6
ok i think i know what you mean...but check me

the top right force for instance (-Q) would be made the top vertice of a triangle. You would do cospi/4 (45 deg) x the hypotenuse force to get the x-axis force??
 

What is electricity?

Electricity is a form of energy that results from the flow of electric charge. It can be found in nature, such as in lightning, or can be artificially generated through various means, such as power plants.

What is magnetism?

Magnetism is a force that causes certain materials to attract or repel each other. It is caused by the motion of electric charges and can be found in natural magnets, such as lodestones, or can be artificially created through the use of electricity.

How are electricity and magnetism related?

Electricity and magnetism are closely related and are actually two aspects of the same fundamental force, known as electromagnetism. Moving electric charges create magnetic fields, and changing magnetic fields create electric fields.

What are the practical applications of electricity and magnetism?

Electricity and magnetism have many practical applications, such as powering appliances, generating light and heat, and powering electronic devices. They are also essential in industries such as transportation, communication, and healthcare.

What is the difference between AC and DC electricity?

AC (alternating current) electricity is the type of electricity that is used in most homes and businesses. It constantly changes direction and is delivered through power lines. DC (direct current) electricity flows in one direction and is commonly used in batteries and electronic devices.

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