In fact, a twofold increase in q would be accompanied by a twofold increase in F. But according to Coulomb's law, more charge also means more electric force ( F). But with a little extra thinking you might achieve insight, a state much better than bliss.) Increasing the quantity of charge on the test charge - say, by a factor of 2 - would increase the denominator of the equation by a factor of 2. But if you think about it a little while longer, you will be able to answer your own question. So how could electric field strength not be dependent upon q if q is in the equation? Good question. Ignorance is bliss.) After all, the quantity of charge on the test charge ( q) is in the equation for electric field.

(Of course if you don't think at all - ever - nothing really bothers you. If you think about that statement for a little while, you might be bothered by it. The electric field strength is not dependent upon the quantity of charge on the test charge. Electric field is the force per quantity of charge on the test charge. Recall that the electric field strength is defined in terms of how it is measured or tested thus, the test charge finds its way into the equation. The symbol q in the equation is the quantity of charge on the test charge (not the source charge). Since there are two charges involved, a student will have to be ultimately careful to use the correct charge quantity when computing the electric field strength. The equation for electric field strength ( E) has one of the two charge quantities listed in it. In the electric world, it takes two to attract or repel. Two charges would always be necessary to encounter a force. In the above discussion, you will note that two charges are mentioned - the source charge and the test charge. In this case, the standard metric units are Newton/Coulomb or N/C.

Since electric field is defined as a force per charge, its units would be force units divided by charge units. The standard metric units on electric field strength arise from its definition. If the electric field strength is denoted by the symbol E, then the equation can be rewritten in symbolic form as. The magnitude of the electric field is simply defined as the force per charge on the test charge. As is usually the case, this force will be denoted by the symbol F. When placed within the electric field, the test charge will experience an electric force - either attractive or repulsive.

The test charge has a quantity of charge denoted by the symbol q. The charge that is used to measure the electric field strength is referred to as a test charge since it is used to test the field strength. The strength of the source charge's electric field could be measured by any other charge placed somewhere in its surroundings. This electric charge creates an electric field since Q is the source of the electric field, we will refer to it as the source charge.

Let's suppose that an electric charge can be denoted by the symbol Q. The magnitude of the electric field strength is defined in terms of how it is measured. In this section of Lesson 4, we will investigate electric field from a numerical viewpoint - the electric field strength.Įlectric field strength is a vector quantity it has both magnitude and direction. The strength of the electric field is dependent upon how charged the object creating the field is and upon the distance of separation from the charged object. The charge alters that space, causing any other charged object that enters the space to be affected by this field. All charged objects create an electric field that extends outward into the space that surrounds it. It was stated that the electric field concept arose in an effort to explain action-at-a-distance forces. In the previous section of Lesson 4, the concept of an electric field was introduced.

Intensity equation