(Conceptual) questions about capacitors, circuits

In summary, a capacitor is an electronic component that stores and releases electrical energy through the use of conductive plates and an insulating material. Its capacitance is determined by the surface area, distance, and dielectric material used. Capacitors can affect circuit behavior in different ways, such as blocking certain frequencies or smoothing out voltage fluctuations. Common uses of capacitors in everyday life include electronic devices, power systems, audio equipment, and flashlights.
  • #1
ustudent
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I have (conceptual) questions about this question posted before:

https://www.physicsforums.com/showthread.php?t=386071

On the second part of the question (part B: The switch is opened at t = 0s. At what time has the charge on the capacitor decreased to 12% of its initial value?), why does the capacitor only discharge through the 10 ohm and 40 ohm resistors? Why doesn't any charge reach the battery or the 60 ohm resistor?

Thanks.
 
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  • #2
because the switch is OPEN...so it's an infinite resistance...no current flows there.
 

1. What is a capacitor and how does it work?

A capacitor is an electronic component that is used to store and release electrical energy. It consists of two conductive plates separated by an insulating material called a dielectric. When a voltage is applied to the capacitor, one plate becomes positively charged while the other becomes negatively charged. This creates an electric field between the plates, allowing the capacitor to store energy. When the capacitor is connected to a circuit, it releases the stored energy in the form of an electrical current.

2. How is the capacitance of a capacitor determined?

The capacitance of a capacitor is determined by the surface area of the plates, the distance between the plates, and the type of dielectric material used. The larger the surface area and smaller the distance, the higher the capacitance. Different materials have different abilities to store electrical energy, which is reflected in their dielectric constant. The capacitance can also be altered by changing the voltage applied to the capacitor.

3. What is the difference between series and parallel circuits?

In a series circuit, components are connected one after another in a single loop. This means that the current flowing through each component is the same, and the voltage is divided among the components. In a parallel circuit, components are connected in multiple branches, allowing the current to flow through each component independently. This means that the voltage across each component is the same, but the current is divided among the branches.

4. How do capacitors affect the behavior of a circuit?

Capacitors can have various effects on a circuit, depending on their placement and values. In a DC circuit, a capacitor can act as an open circuit, preventing current from flowing. In an AC circuit, capacitors can be used to block certain frequencies, allowing only certain signals to pass through. They can also be used to smooth out voltage fluctuations and store energy for later use.

5. What are some common uses of capacitors in everyday life?

Capacitors have many practical applications in everyday life. They are commonly used in electronic devices, such as computers, TVs, and smartphones, to store energy and regulate voltage. In power systems, capacitors are used to improve power factor and reduce energy losses. Capacitors are also used in audio equipment to filter out unwanted frequencies and improve sound quality. Additionally, they are used in flashlights and camera flashes to store electrical energy and release it in short bursts.

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