Find the electrostatic potential above loop of charge Q?

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SUMMARY

The discussion focuses on calculating the electrostatic potential at a point (0, 0, D) above a circular wire of charge Q uniformly distributed in the z = 0 plane with radius R. The key formula used is V = 1/(4πε0)∫dq/r, where r is the distance from the wire to the point of interest, calculated as r = √(R² + D²). The user emphasizes that electrostatic potential is a scalar quantity, and thus only the perpendicular components of the charge distribution contribute to the potential at the specified point.

PREREQUISITES
  • Understanding of electrostatic potential and its scalar nature
  • Familiarity with calculus, specifically integration techniques
  • Knowledge of point charge potential formula
  • Basic concepts of charge distribution along a circular wire
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  • Learn about the application of integration in calculating potentials in electrostatics
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Students in physics, particularly those studying electromagnetism, as well as educators and anyone interested in understanding electrostatic potential calculations in relation to charge distributions.

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Homework Statement


An electric charge Q is uniformly distributed along a thin circular wire situated in the z = 0 plane at x2 + y2 = R2 . Determine the electrostatic potential at the point (0, 0, D).

Homework Equations

The Attempt at a Solution


I figured the only components that mattered would be the one perpendicular to the wire since the parallel components would cancel with the other side of the wire. But I'm not sure what equation to use, or how to approach this. I also found tan of the angle between the point and the loop is R/D, not sure if I need that?

Thanks in advance.
 
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Keep in mind that electrostatic potential is not a vector quantity. So, there are no components. You'll need to know the formula for the potential of a point charge. Break the circular ring into infinitesimal bits of charge, each bit acts like a point charge.
 
So potential due to a continuous distribution of charge : V= 1/(4πε0)∫dq/r

Where r is the distance of the wire to the point at which you are trying to find the potential. In this case, D.
So since the wire has a radius R. The r=√(R2+D). This is because all points along the ring are at the same distance from the point at (0,0,D).

So then plugging this into the first equation, do you notice anything interesting? Perhaps a constant you can factor out leaving you with an easy integral.
 
Thanks for the help, figured it out now. :)
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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