How can electric potential be high

Electronic circuits must be able to store energy and transfer it to other forms like heat, light, or motion. The stored energy of a circuit is called electric potential energy. To understand potential energy we need to understand energy in general. Energy is defined as the ability of an object to do work on another object, which means moving that object some distance.

Energy comes in many forms , some we can see like mechanical and others we can't like chemical or electrical. Regardless of what form it's in, energy exists in one of two states : kinetic or potential. An object has kinetic energy when it's in motion. The amount of kinetic energy an object has depends on its mass and speed. Potential energy , on the other hand, is a stored energy when an object is at rest.

It describes how much work the object could do if set into motion. It's an energy we can generally control. When an object is set into motion, its potential energy transforms into kinetic energy.

Let's go back to using gravity as an example. A bowling ball sitting motionless at the top of Khalifa tower has a lot of potential stored energy.

Once dropped, the ball--pulled by the gravitational field--accelerates towards the ground. As the ball accelerates, potential energy is converted into kinetic energy the energy from motion. Eventually all of the ball's energy is converted from potential to kinetic, and then passed on to whatever it hits.

When the ball is on the ground, it has a very low potential energy. Just like mass in a gravitational field has gravitational potential energy, charges in an electric field have an electric potential energy. A charge's electric potential energy describes how much stored energy it has, when set into motion by an electrostatic force, that energy can become kinetic, and the charge can do work. Observe that the 1 kg mass held at a height of 2 meters has the same potential energy as a 2 kg mass held at a height of 1 meter.

Potential energy depends upon more than just location; it also depends upon mass. In this sense, gravitational potential energy depends upon at least two types of quantities:. So it is improper to refer to high positions within Earth's gravitational field as high potential energy positions.

But is there a quantity that could be used to rate such heights as having great potential of providing large quantities of potential energy to masses that are located there?

While not discussed during the unit on gravitational potential energy, it would have been possible to introduce a quantity known as gravitational potential - the potential energy per kilogram. Gravitational potential would be a quantity that could be used to rate various locations about the surface of the Earth in terms of how much potential energy each kilogram of mass would possess when placed there.

Gravitational potential is a location-dependent quantity that is independent of the mass of the object experiencing the field. Gravitational potential describes the effects of a gravitational field upon objects that are placed at various locations within it.

If gravitational potential is a means of rating various locations within a gravitational field in terms of the amount of potential energy per unit of mass, then the concept of electric potential must have a similar meaning. Consider the electric field created by a positively charged Van de Graaff generator.

The direction of the electric field is in the direction that a positive test charge would be pushed; in this case, the direction is outward away from the Van de Graaff sphere.

Work would be required to move a positive test charge towards the sphere against the electric field. The amount of force involved in doing the work is dependent upon the amount of charge being moved according to Coulomb's law of electric force. The greater the charge on the test charge, the greater the repulsive force and the more work that would have to be done on it to move it the same distance.

If two objects of different charge - with one being twice the charge of the other - are moved the same distance into the electric field, then the object with twice the charge would require twice the force and thus twice the amount of work.

This work would change the potential energy by an amount that is equal to the amount of work done. Thus, the electric potential energy is dependent upon the amount of charge on the object experiencing the field and upon the location within the field. Just like gravitational potential energy, electric potential energy is dependent upon at least two types of quantities:. While electric potential energy has a dependency upon the charge of the object experiencing the electric field, electric potential is purely location dependent.

Electric potential is the potential energy per charge. The concept of electric potential is used to express the effect of an electric field of a source in terms of the location within the electric field.

A test charge with twice the quantity of charge would possess twice the potential energy at a given location; yet its electric potential at that location would be the same as any other test charge. A positive test charge would be at a high electric potential when held close to a positive source charge and at a lower electric potential when held further away.

In this sense, electric potential becomes simply a property of the location within an electric field. Suppose that the electric potential at a given location is 12 Joules per coulomb, then that is the electric potential of a 1 coulomb or a 2 coulomb charged object. Stating that the electric potential at a given location is 12 Joules per coulomb, would mean that a 2 coulomb object would possess 24 Joules of potential energy at that location and a 0.

As we begin to discuss electric circuits, we will notice that a battery powered electric circuit has locations of high and low potential.

Charge moving through the wires of the circuit will encounter changes in electric potential as it traverses the circuit. With a P and an N, it's like there's an imaginary spring between them that's stretched beyond its natural length, and it wants to pull them together. With two P's or two N's, you can imagine the spring is compressed a lot, and pushes the objects away. Scientists call this electrical potential energy, because it's the energy that charged objects have based on their positions relative to one another, just like gravitational potential energy is the energy that things with mass have based on their positions relative to one another.

In other words, charged objects create a "potential field" in which other charges have electric potential energy, in the same way that the Earth produces a gravitational potential field and things in the field have gravitational potential energy.