# Answering General Questions: Electric Field, Potential, Capacitors

• moorec32
In summary, the conversation discusses questions related to electric potential, electric field, and energy stored in a capacitor. It is concluded that the electric field does not necessarily have to be zero if the potential at a point is zero. An example is given to illustrate this concept. The change in energy stored in a capacitor when a dielectric is inserted depends on whether the capacitor is isolated or connected to a battery. Lastly, it is questioned whether there can be a point on the line joining two equal positive charges where the electric field and potential are both zero. The conversation ends with a request for further explanation and attempts at answering the questions.
moorec32
I'm having trouble answering these questions and i was curious to see how other would answer them:

If the potential at a point is zero, must the electric field also be zero? (No)
Give an example.

How does the energy stored in a capacitor change when a dielectric is inserted if (a) the capacitor is isolated so Q doesn't change, (b) the capacitor remains connected to a battery so V doesn't change.

If there is a point along the line joining two equal positive charges where the electric field is zero? Where the electric potential is zero? Explain.

First you should give your answers with your attempts at the explanation, so that we can understand your thoughts on these. Then you'll get all the help needed.

I would approach these questions by first clarifying the concepts involved. The electric field refers to the force per unit charge experienced by a test charge at a given point, while the electric potential is the work required to move a unit charge from a reference point to a specific point in an electric field. A capacitor is a device that stores electric charge and energy.

To answer the first question, if the potential at a point is zero, it does not necessarily mean that the electric field is also zero. This is because the electric field is dependent on the gradient of the potential, and at a point where the potential is zero, the gradient can still have a non-zero value. An example of this can be seen in a uniform electric field, where the potential is constant but the electric field is non-zero.

Moving on to the second question, when a dielectric is inserted into a capacitor, the energy stored in the capacitor changes. In an isolated capacitor (where the charge remains constant), the energy stored increases because the dielectric material reduces the electric field, thus decreasing the potential difference between the plates. On the other hand, in a capacitor connected to a battery, the energy stored remains the same because the battery maintains a constant potential difference between the plates.

For the final question, if there is a point along the line joining two equal positive charges where the electric field is zero, there will also be a point where the electric potential is zero. This is because the electric field and potential are directly related and any point where the electric field is zero will also have a zero potential. This can be seen in the case of two equal positive charges, where the electric field is zero at the midpoint between the two charges and the potential is also zero at this point.

In conclusion, understanding the concepts of electric field, potential, and capacitors is crucial in answering these questions. It is important to remember that these concepts are interrelated and changes in one can affect the others. By clarifying these concepts, we can better understand and answer these questions accurately.

## What is an electric field?

An electric field is a physical property that describes the influence that a charged particle exerts on other charged particles in its vicinity. It is represented as a vector quantity, with both magnitude and direction.

## How is the strength of an electric field measured?

The strength of an electric field is measured in units of Newtons per Coulomb (N/C). This unit represents the amount of force that would be exerted on a unit test charge placed in the field. The stronger the electric field, the greater the force exerted on the test charge.

## What is electric potential?

Electric potential is a measure of the potential energy per unit charge at a given point in space. It is represented in units of volts (V) and is a scalar quantity. Electric potential is related to electric field by the equation V = Ed, where E is the electric field strength and d is the distance between two points.

## How is electric potential different from electric field?

While electric field describes the strength and direction of the force exerted on a charged particle, electric potential describes the energy per unit charge at a given point in space. In other words, electric field is a vector quantity while electric potential is a scalar quantity.

## What is the role of capacitors in an electric circuit?

A capacitor is a device that stores electric charge and is commonly used in electric circuits. It consists of two conductive plates separated by an insulating material. The role of a capacitor is to store energy in the form of an electric field and release it when needed, allowing for the smooth flow of current in a circuit.

• Introductory Physics Homework Help
Replies
6
Views
458
• Introductory Physics Homework Help
Replies
4
Views
514
• Introductory Physics Homework Help
Replies
8
Views
1K
• Introductory Physics Homework Help
Replies
14
Views
838
• Introductory Physics Homework Help
Replies
1
Views
286
• Introductory Physics Homework Help
Replies
5
Views
1K
• Introductory Physics Homework Help
Replies
6
Views
2K
• Introductory Physics Homework Help
Replies
1
Views
1K
• Introductory Physics Homework Help
Replies
18
Views
2K
• Introductory Physics Homework Help
Replies
3
Views
1K