Find Dielectric Constant from Parallel Plate Capacitor Problem

In summary, the conversation discusses how to calculate the dielectric constant of a material placed between the plates of a parallel plate capacitor. It is mentioned that the capacitance is affected by the presence of a dielectric, but the charge on the plates remains the same. Using the equation Q=CV and comparing the capacitance before and after inserting the dielectric, the dielectric constant can be calculated.
  • #1
JordanHood
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Homework Statement


A parallel plate capacitor has a capacitance of 1.5µF with air between the plates. The capacitor is connected a 12V battery and charged. The battery is then removed. When a dielectric is placed between the plates, a potential difference of 5.0V is measured across the plates. What is the dielectric constant of the material?

Homework Equations

The Attempt at a Solution


I know that Q=CV. however this is the only equation I find relevant as all the other equations I know for finding the dielectric constant involve area and distance between the plates. Can someone just help me get started with this question?
 
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  • #2
Inserting a dielectric will increase the capacitance but charge on the the plates will be same. Can you write an equation with this information and find the new capacitance? Comparing the two capacitances, you can calculate the dielectric constant of the new capacitor.
 

1. How do I calculate the dielectric constant from a parallel plate capacitor problem?

To calculate the dielectric constant from a parallel plate capacitor problem, you will need to know the capacitance, the area of the plates, and the distance between them. The formula is given by: K = C x d / A, where K is the dielectric constant, C is the capacitance, d is the distance between the plates, and A is the area of the plates.

2. What is the significance of the dielectric constant in a parallel plate capacitor?

The dielectric constant, also known as the relative permittivity, is a measure of how easily a material can be polarized by an electric field. In a parallel plate capacitor, the dielectric constant affects the capacitance of the capacitor, as it determines the strength of the electric field between the plates.

3. Can the dielectric constant be greater than 1?

Yes, the dielectric constant can be greater than 1. Materials with a dielectric constant greater than 1 are known as "polarizable" materials, meaning they can be easily polarized by an electric field. Examples include water, glass, and many plastics.

4. How does the dielectric constant affect the capacitance of a parallel plate capacitor?

The dielectric constant has a direct relationship with the capacitance of a parallel plate capacitor. As the dielectric constant increases, the capacitance also increases. This is because a higher dielectric constant means that the material between the plates is better at storing electric charge, leading to a higher capacitance.

5. Can the dielectric constant change over time?

Yes, the dielectric constant can change over time. Factors such as temperature, pressure, and mechanical stress can affect the dielectric constant of a material. In some cases, the dielectric constant can even change in response to an electric field. However, for most materials, the dielectric constant remains relatively constant.

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