Year 12 / Electromagnetism
Voltage is an energy difference.
Potential difference is the change in electric potential energy per unit charge. Use ΔU = qΔV with the sign of q. A positive charge loses potential energy moving to lower potential, while a negative charge loses it moving to higher potential.
If only electric forces do work, the gain in kinetic energy is the loss of electric potential energy. An electron volt is an energy unit: the energy associated with moving one elementary charge through one volt.
Energy per unit charge
Explore the relationship
ΔU = qΔV. A negative charge gains potential energy when moved to a lower potential.
Potential energy change / μJ
Tap or focus a plotted point to read its values.
View plotted data as a table
| Series | Potential difference / V | Potential energy change / μJ |
|---|---|---|
| Potential energy change / μJ | 0 | 0 |
| Potential energy change / μJ | 1.66667 | 3.33333 |
| Potential energy change / μJ | 3.33333 | 6.66667 |
| Potential energy change / μJ | 5 | 10 |
| Potential energy change / μJ | 6.66667 | 13.3333 |
| Potential energy change / μJ | 8.33333 | 16.6667 |
| Potential energy change / μJ | 10 | 20 |
| Potential energy change / μJ | 11.6667 | 23.3333 |
| Potential energy change / μJ | 13.3333 | 26.6667 |
| Potential energy change / μJ | 15 | 30 |
| Potential energy change / μJ | 16.6667 | 33.3333 |
| Potential energy change / μJ | 18.3333 | 36.6667 |
| Potential energy change / μJ | 20 | 40 |
| Potential energy change / μJ | 21.6667 | 43.3333 |
| Potential energy change / μJ | 23.3333 | 46.6667 |
| Potential energy change / μJ | 25 | 50 |
| Potential energy change / μJ | 26.6667 | 53.3333 |
| Potential energy change / μJ | 28.3333 | 56.6667 |
| Potential energy change / μJ | 30 | 60 |
| Potential energy change / μJ | 31.6667 | 63.3333 |
| Potential energy change / μJ | 33.3333 | 66.6667 |
| Potential energy change / μJ | 35 | 70 |
| Potential energy change / μJ | 36.6667 | 73.3333 |
| Potential energy change / μJ | 38.3333 | 76.6667 |
| Potential energy change / μJ | 40 | 80 |
| Potential energy change / μJ | 41.6667 | 83.3333 |
| Potential energy change / μJ | 43.3333 | 86.6667 |
| Potential energy change / μJ | 45 | 90 |
| Potential energy change / μJ | 46.6667 | 93.3333 |
| Potential energy change / μJ | 48.3333 | 96.6667 |
| Potential energy change / μJ | 50 | 100 |
| Potential energy change / μJ | 51.6667 | 103.333 |
| Potential energy change / μJ | 53.3333 | 106.667 |
| Potential energy change / μJ | 55 | 110 |
| Potential energy change / μJ | 56.6667 | 113.333 |
| Potential energy change / μJ | 58.3333 | 116.667 |
| Potential energy change / μJ | 60 | 120 |
| Potential energy change / μJ | 61.6667 | 123.333 |
| Potential energy change / μJ | 63.3333 | 126.667 |
| Potential energy change / μJ | 65 | 130 |
| Potential energy change / μJ | 66.6667 | 133.333 |
| Potential energy change / μJ | 68.3333 | 136.667 |
| Potential energy change / μJ | 70 | 140 |
| Potential energy change / μJ | 71.6667 | 143.333 |
| Potential energy change / μJ | 73.3333 | 146.667 |
| Potential energy change / μJ | 75 | 150 |
| Potential energy change / μJ | 76.6667 | 153.333 |
| Potential energy change / μJ | 78.3333 | 156.667 |
| Potential energy change / μJ | 80 | 160 |
| Potential energy change / μJ | 81.6667 | 163.333 |
| Potential energy change / μJ | 83.3333 | 166.667 |
| Potential energy change / μJ | 85 | 170 |
| Potential energy change / μJ | 86.6667 | 173.333 |
| Potential energy change / μJ | 88.3333 | 176.667 |
| Potential energy change / μJ | 90 | 180 |
| Potential energy change / μJ | 91.6667 | 183.333 |
| Potential energy change / μJ | 93.3333 | 186.667 |
| Potential energy change / μJ | 95 | 190 |
| Potential energy change / μJ | 96.6667 | 193.333 |
| Potential energy change / μJ | 98.3333 | 196.667 |
| Potential energy change / μJ | 100 | 200 |
Explore: Switch the sign of the charge and compare energy changes for the same potential difference.
A +4 μC charge moves through a potential drop of 30 V.
- ΔU = 4 × × (−30) = −1.2 × J.
- If no other work occurs, kinetic energy increases by 1.2 × J.
Assumed knowledge
Energy conservation.
Learning checkpoints & source
YOUR LEARNING CHECKPOINT- Relate potential difference to potential energy change.
- Account for charge sign and kinetic energy.
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