Electric Fields

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​Electric Fields

What is an Electric Field?

An electric field is an invisible force field created by the attraction and repulsion of electrical
charges (the cause of electric flow), and is measured in Volts per meter (V/m). The intensity of the
electric field decreases with distance from the field source.

Electric field strength is a quantitative expression of the intensity of an electric field at a particular
location. The standard unit is the volt per meter. It is the strength of an electric field that is equal to the
force on a positive test charge divided by the strength of the test charge.

What is Electric Field Strength?

Formula:

When two charges interacting through a field change relative position, the energy stored in the field is
changed. If, and only if, the charge q is a point charge or a uniformly charged sphere, you can calculate its
electric field from Coulomb’s law. Coulomb's law describes the strength of the electrostatic force
(attraction or repulsion) between two charged objects. The electrostatic force is equal to the charge of
object 1 times the charge of object 2, divided by the distance between the objects squared, all times the
Coulomb constant (k).

What is Coulomb's Law?

Formula:

Electric potential difference, also known as voltage, is the external work needed to bring a charge from one
location to another location in an electric field. Electric potential difference is the change of potential
energy experienced by a test charge that has a value of +1 . In other words, it is the work needed to move a
positive test charge from one point to another, divided by the magnitude of the test charge. It can also be
thought of as the change in electric potential energy per unit charge.

What is Electric Potential Difference?

Formula:

W

If you lift the ball against the gravitational force, you do work on the ball. The gravitational potential energy
in the ball-Earth system increases. The same is true in electrical interactions. The work performed moving
a charged particle in an electric field can result in the particle gaining electric potential energy, kinetic
energy, or both.

What is Energy and Electric Potential?

The electrostatic force exists between two charges placed at a distance. The magnitude of electrostatic
force depends on the magnitude of each charge and the distance between them. When two positive
charges or two negative charges are brought together, then the two charges repel each other.

What is Electrostatic Force?

Multiple Choice

What is Coulomb's Formula?

• $$E=\frac{F}{Q}$$

• $$\Delta V=\frac{W}{q}$$

• $$F=\frac{kq^1q^2}{r^2}$$

• $$C=\frac{q}{\Delta V}$$

Multiple Choice

What is Electric Field Strength Formula?

• $$E=\frac{F}{Q}$$

• $$\Delta V=\frac{W}{q}$$

• $$F=\frac{kq^1q^2}{r^2}$$

• $$C=\frac{q}{\Delta V}$$

Multiple Choice

What is Electric Potential Difference Formula?

• $$E=\frac{F}{Q}$$

• $$\Delta V=\frac{W}{q}$$

• $$F=\frac{kq^1q^2}{r^2}$$

• $$C=\frac{q}{\Delta V}$$

Multiple Choice

Electric Potential Difference is also known as

• Gravitational Potential Energy

• Electricity

• Voltage

• Natural Energy

Multiple Select

A test charge must always be

• Bigger than the actual charge

• Positive

• Smaller than the actual charge

• Negative

Draw

How does the electric field look like when 2 unlike charges are brought close together?