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Electric Potential & Electric Potential Energy (EPE). Height = Electric Potential Electric Potential a.k.a Voltage. Height in a gravitational field is analogous to electric potential or voltage in an electric field. Electric Potential is also known as VOLTAGE.
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Height = Electric PotentialElectric Potential a.k.a Voltage Height in a gravitational field is analogous to electric potential or voltage in an electric field. Electric Potential is also known as VOLTAGE. Lifting mass through a height, “h” of 5m is analogous to lifting a charge, “q” through a height of 5V.
Electric Potential a.k.a Voltage A mass at height = 0m will not fall, as it is at ground level. Similarly, A charge with voltage = 0V will not move, as it is at ground state. A charge at 100V is at a greater “height” in an electric field when compared with one at 5V.
Height and Voltage Release a mass or a charge, and they fall to a lower elevation (to 0m or 0V). You need an elevation difference for a mass to move. You can remain at a height of 10,000m, but will not fall unless there is an elevation difference. Similarly, you need a voltage difference for a charge to move. The charge can remain at 10,000V, but will not move unless there is a voltage difference.
Van-De-Graff Generator A Van-De-Graff generator will not discharge electrons unless a lower voltage (Grounding rod) is brought close to it. The person in the picture will build up charges, but will need a lower potential to discharge the charges.
Electric Pressure Electric Potential or Voltage can also be thought of as electric pressure. Electrons can happily exist at very high pressure, but will not flow unless there is a pressure difference. An outlet at 120V has electrons at very high pressure, but there is no pressure difference, so no electrons flow out. When we plug in an appliance, we provide the low pressure, and so electrons start to flow out.
Gravitational height & GPE At first let us understand the relationship between height and Gravitational Potential energy. This will help us understand the similar relationship between the electric voltage and electrical Potential energy.
Gravitational Potential Energy (GPE) Potential Energy is the energy that any object potentially has due to its position. Greater the height, greater the potential energy of a mass on Earth. (That is why objects when dropped from a higher height have more energy and can do more damage.) An object when dropped from a given height will start to lose its GPE and starts to gain Kinetic energy (energy due to motion).
Electrical Potential Energy (EPE) Potential Energy is the energy that any object potentially has due to its position. Greater the Voltage, greater the potential energy of a charge in E field. (That is why charges when attracted from a higher potential to a lower potential have more energy and can do more damage.) A charge when attracted from a higher voltage to a lower voltage, will lose its EPE and gain Kinetic energy (energy due to motion).
Electrical Potential Energy • A charge at 100V is at a greater “height” in an electric field when compared with one at 10V. • A charge will lose its EPE when moving from 100V to 95V and gain EPE when moving from 95V to 100V. • A charge will naturally move from a higher to a lower potential.
Electric Potential Difference = ∆V A charge when moving from a • 100v to a 95 V will have ∆V = 5V (loss of EPE) • 95V to 100V will have ∆V = 5V (Gain of EPE) A charge will naturally move from 100V to a 95V position and lose its energy (EPE). To move it from 95V to 100V, we have to do work (This means we lose energy by doing work) and it gains energy(EPE). This is conservation of Energy. This means that energy can neither be gained nor lost.
∆V Just like when we talk about heights, we assume that we mean height difference, When we talk above voltages, we assume that we mean Voltage difference. Tango and Cash High Transmission Line Repairs
Equi-Potential Lines These are lines in an E field where voltage is constant. A charge on a equi-potential line can move without losing or gaining energy. Equi comes from equal. The lines circling the charges are equi-potential lines.
Electric Potential (V) Electric Potential is defined as the Energy of a charge. Electric Potential = Energy/Charge or V = U/q or ∆V = ∆U/q Unit of Voltage is V, Unit of U(energy) is Joules, Unit of q is in Coulomb.
Voltage Difference ∆V = ∆U/q Here U is the total energy. • U can be Potential energy, Kinetic Energy or sum of these energies together. • (KE = (½)mv2 , here “v” is the velocity of the charge.) - or it can be work done on or by the charge.
Voltage Difference I will not give you the actual derivation, but V= kq/d Or V = Ed (since E=kq/d2) From this we can see that the unit of E can also be V/m or (N/C) as we know earlier.
EPE • Using all the given equations, we get ∆EPE = qEd That is change in the electric potential energy is equal to the charge times the electric field times the distance.
EPE and Voltage • Electric Potential or Voltage is a scalar quantity and so direction does not matter. • Recapping, • Electric Potential is the Energy of each charge. • Electric Potential energy is the total energy due to all the charges present.
