Is the electric potential energy of two unlike charges postive or negative? What about two like charges? What is the significance of the sign of the potential energy in each case? (23/19)

• juano says:

Two unlike charges are by definition one positive and one negative. Think of the number line from elementary school math. Examples to illustrate: Negative 2 volts and positive 2 volts have a potential, or difference of 4 volts. If two like charges have the same voltage, then there is no potential energy. If there are two positive charges, but one is 2 volts and one is 4 volts there is a potential energy of 2 volts between them. Think of the number line again. Both are positive but there is a potential of 2 between them. The same holds for negative charges. Potential should never be a negative number because potential is the distance between two points on a number line, and that distance should be either zero or a positive number.

Then what are people saying when they say that there is negative x volts? That means that the voltage is being measured against another pole that is x volts more positive. In other words it is a relative term. It is -x volts, but only relative to the other more positive pole,

• blueridgemotors says:

Electricity is the relationship between the Negative & Positive. The potenial is the energy that drives the circuit and that is measured in ammpres. There is a differance between the negative and the positive and it is known as polarity. A circuit is a continous loop and within the loop there is resistance and that is known as a load. Like charges are reactive and can exist within a normal circuit which create an abnormality. Based upon the information given, unlike charges do not work well and are the main cause of electrical failures, early death to fight bulbs and motors. Measuring the potential of such a circuit is counter productive and it is caodic.
The cicuit does work, meaning that work can be measured in horse power or how bright a light bulb shines. Work is resistance and although resistance is present within a single loop work is not measured until that loop does or goes through a helix manuver. Understanding this phenomina is very simple and can be demonstrated by taking a strip of paper 10 x 1 x .003. Mark one end with an N and the other with an S. Form a circle with the ribbon and notice that the N & S will meet. Who is to say that the N is no longer N when it enters the domain of the S. To remove the contridiction place the ribbon back on the table and flip it over and mark the end that has the N on the bottom side with an S. The ribbon is of three dimensions and the space of the thickness (.003) is like a magnet so no laws of physics are broken. Now, recreate your loop with a twist so that the circle is the circuit wherebye North is North and South is South. This is how the magnetic field of the Earth works and why the winds blow from West to East and from East to West in the Southern Hemisphere. Can you measure the potential in that circuit?

• Philip J says:

Potential is relative to an arbitrary reference level. If you set the zero reference (ground potential) at a separation of 1 mm, and the charges are 2 mm apart, then they have positive potential because it took energy (work) to pull them apart from 1 mm to 2 mm. Allowing the charges to move to 1 mm apart will release energy. They want to be close, so if they are closer than the reference level that gives them negative potential.

• Andre P says:

Energy is always positive in classic physics and that is true regardless of whether it’s potential or kinetic.
Energy is the amount of work available.
Work equals F*x, ie. force time displacement.
With a positive and a negative charge F and x go towards the two. With two like charges BOTH F and x change sign, thus the positive value of energy is preserved. ie. Force points the other way, and the displacement will be the other way. No sign-change after the multiplication.