10.4 Dielectrics

• Dielectrics increase capacitance by reducing the electric field between the plates
• What is the formula for the capacitance of a parallel-plate capacitor with a dielectric?

  $C =$$\kappa \frac{\epsilon_{0} A}{d}$
• The dielectric constant represents the factor by which a material reduces the electric field compared to vacuum
• What does the dielectric constant represent?

  Reduction of electric field
• What happens to dielectric molecules when placed in an electric field?

  They align and polarize
• What is the primary difference between dielectrics and conductors in terms of electric charge flow?

  Dielectrics cannot flow charges
• Capacitance is inversely proportional to the potential difference between capacitor plates.


  True
• Which material has the highest dielectric constant?

  Water
• What is the role of polarization in dielectrics within capacitors?

  Reduces electric field strength
• What happens to dielectrics when placed in an electric field?

  They become polarized
• Capacitance is inversely proportional to potential difference for a constant charge.


  True
• Conductors can be polarized when placed in an electric field.

  False
• Steps in the polarization process of a dielectric in an electric field:

  1️⃣ Dielectric molecules align with the electric field

  2️⃣ An internal electric field is created

  3️⃣ The overall electric field strength is reduced
• The dielectric constant of vacuum is 1
• The electric field strength in a dielectric is related to the vacuum field strength by the dielectric constant
• Dielectrics increase capacitance by reducing the electric field
• The capacitance of a parallel-plate capacitor with a dielectric is given by $C =$$\kappa \frac{\epsilon_{0} A}{d}$, where $\epsilon_{0}$ is the permittivity of free space
• The electric field in a dielectric is always stronger than in vacuum.

  False
• Conductors reduce the electric field between capacitor plates.

  False
• The electric field in a dielectric is equal to the electric field in vacuum divided by the dielectric constant.


  True
• What is the formula for the capacitance of a parallel-plate capacitor with a dielectric?

  $C =$$\kappa \frac{\epsilon_{0} A}{d}$
• Dielectrics increase capacitance by reducing the potential difference
• Steps in how dielectrics reduce the electric field in a capacitor

  1️⃣ Dielectric is placed in the electric field

  2️⃣ Molecules align to create an internal field

  3️⃣ The internal field opposes the external field

  4️⃣ The overall electric field strength is reduced
• What does the variable \(E_0\) represent in the electric field formula?

  Electric field in vacuum
• Match the properties of dielectrics and conductors:

  Dielectrics ↔️ Cannot flow freely

  Conductors ↔️ Allow free flow of charges
• What is the key difference between dielectrics and conductors in terms of electric charge flow?

  Dielectrics cannot flow freely
• What role do dielectrics play in preventing breakdown in capacitors?

  Increase breakdown voltage
• Match the variables with their units:

  Area ↔️ m^2

  Plate Separation ↔️ m

  Dielectric Constant ↔️ Dimensionless
• What are two effects of inserting a dielectric material between capacitor plates?

  Increase capacitance, prevent breakdown
• The dielectric material reduces the electric field and increases charge storage
• Match the material with its approximate dielectric constant:

  Vacuum ↔️ 1

  Air ↔️ 1.0006

  Rubber ↔️ 3

  Glass ↔️ 4-7

  Water ↔️ 80
• Higher dielectric constants indicate a greater ability to reduce the electric field compared to vacuum.


  True
• Polarization in dielectrics creates an internal electric field that opposes the external field.

  True
• Conductors can be polarized when placed in an electric field.

  False
• Dielectrics reduce the electric field strength by aligning their molecules
• Higher values of the dielectric constant indicate a greater ability to reduce the electric field
• When a dielectric material is placed between capacitor plates, its molecules become aligned with the applied electric field
• Inserting a dielectric material between capacitor plates reduces the risk of breakdown.


  True
• What is the key difference between dielectrics and conductors regarding electric charge flow?

  Dielectrics do not allow free flow of charges
• What does the dielectric constant of a material indicate?

  Electric field reduction