Calculate Electrostatic Force Between Two Plates

In summary, The electrostatic force attracting two plates can be calculated by first finding the surface charge density on each plate, which is equal to the charge divided by the area of the plate. Then, using the formula Q = AeV/d, where Q is the charge, A is the area of the plate, V is the voltage applied, and d is the separation between the plates. Finally, the force can be determined by multiplying the charge by the electric field, which is equal to eAV^2/(2d^2). It should be noted that a correction factor may need to be applied in practical situations.
  • #1
ak_47_boy
7
0
Hello, first post here. I hope this is in the right section.
I have spent an hour or so surfing the net and could not figure this out (i am bad at physics).

How do you figure out the electrostatic force attracting two plates? The plates are 2sq/m, have a 0.006m spacing, and have 10000 volts of potential difference.
 
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  • #2
Welcome. Since you said you were “bad” at Physics, I’m trying to give you a detailed solution.

When a voltage V is applied across the plates, suppose the plates receive charges +Q and -Q. The surface charge density on the plates are +s and –s, where s=Q/A. If the plates were infinite in extent, then each would produce an electric field of magnitude
s/(2e) = Q/(2Ae) --(1), where I’m writing e for epsilon_naught. Let d be the separation between the plates.

The sum of the fields of both the plates E = Q/(Ae) and V=E*d
=> Q = AeV/d --(2).

So, force on one plate due to field of other = Q*field = Q*Q/(2Ae) (from 1)
= eAV^2/(2d^2) (from 2).

Note that the electric field of each plate has been calculated for the case when each plate in infinite in extent. In practice, some correction factor is introduced.
 
  • #3


Sure, I'd be happy to help you with this calculation. The electrostatic force between two parallel plates can be calculated using Coulomb's Law, which states that the force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. In this case, the plates have a potential difference of 10000 volts, which means they have a charge of 10000 volts x 2 square meters = 20000 Coulombs (since the units for voltage are equivalent to joules per coulomb). The distance between the plates is 0.006 meters, so the force can be calculated as:

F = (k * q1 * q2) / d^2

Where k is the Coulomb's constant (8.99 x 10^9 N*m^2/C^2), q1 and q2 are the charges on the plates (20000 Coulombs), and d is the distance between the plates (0.006 meters). Plugging in these values gives us:

F = (8.99 x 10^9 N*m^2/C^2) * (20000 C) * (20000 C) / (0.006 m)^2

= 8.99 x 10^9 N*m^2/C^2 * 400000000 C^2 / 0.000036 m^2

= 8.99 x 10^9 N * 400000000 / 0.000036 m^2

= 8.99 x 10^9 N * 11111111111.11 / m^2

= 9.99 x 10^20 N

Therefore, the electrostatic force between the two plates is approximately 9.99 x 10^20 Newtons. I hope this helps and let me know if you have any further questions or need clarification.
 

FAQ: Calculate Electrostatic Force Between Two Plates

How do you calculate the electrostatic force between two plates?

To calculate the electrostatic force between two plates, you will need to know the charge on each plate, the distance between the plates, and the dielectric constant of the material between the plates. You can then use the equation F = (k * q1 * q2)/d^2, where F is the force, k is the Coulomb's constant, q1 and q2 are the charges on the plates, and d is the distance between the plates.

What is Coulomb's constant?

Coulomb's constant, also known as the electrostatic constant, is a proportionality constant that relates the electrostatic force between two charged particles to their charges and the distance between them. Its value is approximately 8.99 x 10^9 Nm^2/C^2.

How does the distance between the plates affect the electrostatic force?

The electrostatic force between two plates is inversely proportional to the square of the distance between them. This means that as the distance between the plates increases, the force decreases, and as the distance decreases, the force increases.

What is the dielectric constant and how does it affect the electrostatic force?

The dielectric constant is a measure of a material's ability to store electrical energy. It affects the electrostatic force between two plates by reducing the force compared to what it would be in a vacuum. This is because the presence of a dielectric material between the plates reduces the strength of the electric field between them.

Can the electrostatic force between two plates ever be repulsive?

Yes, the electrostatic force between two plates can be either attractive or repulsive, depending on the charges on the plates. If the charges on the plates are of the same sign (both positive or both negative), the force will be repulsive. If the charges on the plates are of opposite signs, the force will be attractive.

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