Why is Voltage More Useful Than Electrical Potential Energy?

[GRB 080319B]

Why is electric potential (voltage) necessary? I can see how creating the electric field as the force per unit charge allows the force on one charge in the field of another charge to be calculated and accounts for the observed action at a distance by forces. I don't see the correlation of potential energy/potential like force/field (why voltage is more useful than electrical potential energy)?

 

[Andrew Mason]

Why is electric potential (voltage) necessary? I can see how creating the electric field as the force per unit charge allows the force on one charge in the field of another charge to be calculated and accounts for the observed action at a distance by forces. I don't see the correlation of potential energy/potential like force/field (why voltage is more useful than electrical potential energy)?

Voltage IS potential energy per unit charge. Are you asking why potential energy per unit charge is more useful than potential energy?

AM

 

[Studiot]

One of the less obvious details that causes much confusion is that both potential and potential difference are measure in volts.

So sometimes when we say volts we mean potential and sometimes pd. It can be very confusing if we say one but think of the attributes of the other.

go well

 

[ZapperZ]

Why is electric potential (voltage) necessary? I can see how creating the electric field as the force per unit charge allows the force on one charge in the field of another charge to be calculated and accounts for the observed action at a distance by forces. I don't see the correlation of potential energy/potential like force/field (why voltage is more useful than electrical potential energy)?

I'm not sure whether this is an elementary question, or something more "profound".

Why is electric potential more "useful"?

1. It is a scalar rather than a vector. Anyone dealing with any considerable amount of E&M can tell you it is way easier to solve for a scalar than a vector. In any kind of complex geometry, one solves either Poisson's equation, or the Green's function, which essentially is solving for the potential field. Deriving the electric field after you get that is almost relatively trivial.

2. You need the potential field if you want to use the Hamiltonian of the system.

Zz.

 

[Alex Pikalov]

Electric potential can be more usability in specific problem solving. But it is dependent on concrete problem and personal taste.

Sorry for my English.

 

[sauermaische]

The battery has one terminal at a potential that is higher than the other. What's happening here? Chemical reactions are due to the exchange of electrons between chemicals. When this results in one chemical gaining an excess of electrons and the other a deficit, then a potential difference will exist between the two chemicals. If you attach a copper wire connecting the terminal with an excess of electrons to the terminal with a deficit, then a current will flow to eliminate the discrepancy. If you don't connect a copper wire an electric field will exist, external to the battery, between the two terminals. Electrons can be moved from one place to another to create an excess in one place and a deficit in another by mechanical means. This is the cause of static electricity, where you rub amber with fur, or ball point pen with jumper. Whenever we have an excess of electrons in one place and a deficit in another, then there will be a force impelling the excess to redistribute more evenly.
Just as mass falls through differences of height (in a gravitational field) so charge falls through differences of voltage (in an electrical field). Just as a mass raised in a gravitational field has potential energy, which it releases when it falls; so charge has potential energy in an electrical field, which it releases when it moves to a lower voltage. Volts is a measure of this potential energy. The Volt is just a snappy name for the Joule/Coulomb [i.e. kg.m2/coulomb.s2], that is energy per unit charge.

 

[sauermaische]

The reason why we use potential rather than energy is that we are able to measure potential, but measuring energy is problematic. If you try and measure energy, then you get noise from thermal effects, mechanical effects etc. It's a bugger to do, ask any microwave engineer. It's much easier to measure volts.

 

[ZealScience]

Why is electric potential (voltage) necessary? I can see how creating the electric field as the force per unit charge allows the force on one charge in the field of another charge to be calculated and accounts for the observed action at a distance by forces. I don't see the correlation of potential energy/potential like force/field (why voltage is more useful than electrical potential energy)?

I think it is because pd is PE/charge, which means potential energy of unit charge in that system. Then you don't necessarily know what chargeis put in the system and describe the property of the system.