Current and Resistance

Electrical current is defined as the rate at which charge flows. When there is a large current present, such as that used to run a refrigerator, a large …

The high speed of electrical signals results from the fact that the force between charges acts rapidly at a distance. Thus, when a free charge is forced …

The total amount of current flowing through one unit value of a cross-sectional area is referred to as current density. If the current flow is uniform, …

When a voltage is applied to a conductor, an electrical field is generated, and charges in the conductor feel the force due to the electrical field. The …

When a current moves through any conductor, the conductor causes some level of difficulty for the current to flow. The measure of that difficulty is known …

Many materials exhibit a simple relationship between the values of current, voltage, and resistance, known as Ohm’s law. The current that flows …

In most substances, the current flow is proportional to the voltage applied to it. A simple relationship between the values of current, voltage, and …

Electric power is the product of current and voltage, represented in units of joules per second, or watts. For example, cars often have one or more …

Using electric appliances for a longer period of time consumes more electrical energy and results in a higher electric bill. The energy produced by the …

The total amount of current flowing per unit cross-sectional area is called the current density. Hence, the current passing through a cross-sectional area …

Current density becomes discontinuous across an interface of materials with different electrical conductivities. The normal component of the current …

In perfect conductors, the electric field inside is always zero due to the abundance of free electrons, which nullify any field by flowing. As a result, …

The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the …