An electric field is an electrostatic force exerted by one electrical charge on another. The strength of the electric field at the position indicated by the dot in (figure 1) is calculated by dividing the total number of electrons in a certain volume (given to us as Q) with the number of electrons outside that volume.

What is the strength of the electric field at the position indicated by the dot in (figure 1)?

If you want to write the answer in full, how is the strength of an electric field indicated?

in the example above, because there are 5.10×10 electrons in the total volume of an atom, divided by 5.10×10 electrons outside that volume. The result is 1.01×10 N/C (the units must always be stated).

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

1. It is the force exerted on a charge that the electric field is acting on.

2. All it means is the number of electrons in a certain volume, divided by the number of electrons outside that volume.

3. It is written as 1×10 N/C (the units must always be stated). A sphere with a radius of 1 meter and an inner radius (which you will use as your sample volume) of 0.1 m would have an electric field strength of 9×10 N/C at its center, since there are 9×10 electrons contained in its volume and 9×10 electrons outside the sphere (total: 9×10).

4. It is the force exerted on an electric charge that the electric field is acting on.

5. It is written as 1×10 N/C (the units must always be stated).

6. It is the number of electrons contained in a certain volume, divided by the number of electrons outside that volume.

7. It is written as 1×10 N/C (the units must always be stated).

## Electric field :

A force exerted on each charge present by its neighbor in the field. The electric field is the same for all charges, one of the fundamental properties of a uniform (or “homogeneous”) field. The SI unit for electric field is the volt (V), 1 V = 1 N/C

The strength of a magnetic field at point “P” is the total number of magnetically charged particles in a certain volume (given to us as q) divided by the number of such particles outside that volume, multiplied by 4πr3/3 where r is the distance from “P”.

### Important points about the strength and direction of electric field :

## 1. The direction of an electric field always points from positive to negative.

A positive charge cannot exist without an associated negative charge so the electric field always points from the positive charges toward the negative charges.

## 2. The strength of an electric field decreases as distance from the charges increases.

The strength of an electric field decreases as the distance from the charges increases because, as it moves away, there are more and more virtual particles that appear between it and the charge. This means that there are less electrons close to a positive charge than further away.

This is because electric field lines point radially outward from positive charges and toward negative charges in a uniform electric field, meaning they spread out equally in all directions (not just in one direction). Both of these points are illustrated in Figure 1.

The equation for calculating the strength of an electric field depends on 3 variables: “q”, “Q”, and “r”.

## 3. q is the electric charge of an object.

This charge can be positive or negative. Q is the amount of electric charge in a certain volume of space. Matter is made up of atoms, and an atom consists of a nucleus surrounded by electrons.

The nucleus contains protons (positively charged) and neutrons (which have no charge). The number of protons in a nucleus defines what element it is, and the number of neutrons defines what isotope it is (atoms with different numbers of neutrons are called isotopes).

## 4. Q is the total number of charges in a certain volume of space.

This includes positive and negative charges. An atom consists of a nucleus surrounded by electrons, so Q is the total number of protons (positively charged) in an object and the number of neutrons (which have no charge).

The number of protons in an atom defines what element it is, and the number of neutrons defines what isotope it is (atoms with different numbers of neutrons are called isotopes).

The constant “C” in the equation below tells us that we need to multiply the number of particles per unit volume by 4πr3/3 where r is the distance from “P”.

## 5. r is the distance from “P”.

This is how we get the strength of an electric field at point “P”, because if you know the electric field at a certain point (electric field lines pointing inwards toward that point), then you can calculate the distance to that point using the inverse square law for electrostatics. The equation below is used to calculate the strength of an electric field at a point.