A 3500-pF air-gap capacitor question

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In summary, we are trying to determine the amount of additional charge that will flow from the battery when a piece of mica is placed between the plates of a 3500-pF air-gap capacitor connected to a 32-V battery. The solution is calculated by subtracting the dielectric constant of air (1) from the dielectric constant of mica (7), resulting in a new dielectric constant of 6. The final answer is 6.7 x 10^-7 Coulomb.
  • #1
skepticwulf
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A 3500-pF air-gap capacitor is connected to a 32-V
battery. If a piece of mica is placed between the plates,
how much charge will flow from the battery?

Homework Equations


C = K€A/d[/B]

The Attempt at a Solution


Q1=C1V1
Q2=C2V2

V1=V2=V
C2=7C1(as only diference between C1 and C2 is the mica and it's K is 7 so it's 7 times C1)
Result: Q2=7.84 x 10^-7Coloumb

**But solution manual say it's 6.7 x 10^-7Columb BECAUSE it calculates the new K by subtracting 1 from 7 (1 is the K of air) ?! Why subtract? totally lost :(
[/B]
 
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  • #2
The question is how much charge is added to the already existing charge to the capacitor, which is Q2-Q1.
 
  • #3
Ahh so by saying "how much charge will flow from the battery?" it means "how much ADDITIONAL/EXTRA charge will flow from the battery?" .. OK I've got got it now but the that part if the question is a bit misty, don't you think?

Thank you!
 

Related to A 3500-pF air-gap capacitor question

1. What is a 3500-pF air-gap capacitor?

A 3500-pF air-gap capacitor is a type of capacitor that has a capacitance value of 3500 picofarads (pF) and an air gap between its two conducting plates. This air gap allows for a higher voltage rating and lower sensitivity to temperature changes compared to other types of capacitors.

2. How does a 3500-pF air-gap capacitor work?

A 3500-pF air-gap capacitor works by storing electrical energy in the form of an electric field between its two conducting plates. When a voltage is applied, electrons collect on one of the plates, creating a negative charge, while the other plate becomes positively charged. This creates an electric field between the plates, which can then be used to store energy.

3. What are the applications of a 3500-pF air-gap capacitor?

A 3500-pF air-gap capacitor is commonly used in high-voltage and high-frequency circuits, such as in power supplies, amplifiers, and radio transmitters. It can also be used in electronic equipment that requires stable and precise capacitance values, such as in medical devices and telecommunications equipment.

4. How is the capacitance of a 3500-pF air-gap capacitor determined?

The capacitance of a 3500-pF air-gap capacitor is determined by the surface area of its plates, the distance between the plates, and the dielectric constant of the material between the plates. In this case, the dielectric is air, which has a dielectric constant of 1. Therefore, the capacitance can be calculated using the formula C = εA/d, where C is the capacitance, ε is the dielectric constant, A is the surface area of the plates, and d is the distance between the plates.

5. How does a 3500-pF air-gap capacitor differ from other types of capacitors?

A 3500-pF air-gap capacitor differs from other types of capacitors in that it has an air gap between its plates, whereas other capacitors may use different dielectric materials such as ceramic, plastic, or electrolytic fluids. This allows for a higher voltage rating and lower sensitivity to temperature changes, making it suitable for use in high-voltage and high-frequency circuits.

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