Handout #21 - Comparison and Contrasts
Between the Electric and Magnetic Forces
Electric phenomena |
Magnetic phenomena |
| All objects can be electrified | Only some objects (such as iron and steel) can be magnetized |
| Non-electrified objects can electrify any object, when rubbed with it in any direction. The result depends only on the materials used. | Only a magnetized object can magnetize iron or steel, when it stroke it in a specific direction. Changing direction affect the result of the magnetization. |
| Electrified object can be uncharged through grounding (conductors) or other ways (easier than demagnetizing) | Magnetized object can be demagnetized through heat and striking (more difficult than to uncharge) |
| A conductor cannot be electrified if grounded (held by hand) | Iron or steel can be magnetized when held. (I.e. there is no such thing as grounding for magnets) |
| A conductor can be used to screen electric effects (Faraday cage) | Iron and steel can be used to screen magnetic forces |
| There are two types of electric forces, attractive and repulsive. | There are two types of magnetic forces, attractive and repulsive. |
| Positive and negative charges (model). Like charges repel, unlike attract. | North and South poles (observable). Like poles repel, unlike attract |
| It is possible to separate positive charges from negative ones. | It is not possible to isolate one pole from the other |
| Electric forces depend on distance. They are weaker the larger is the distance. | Magnetic forces depend on distance. They are weaker the larger is the distance |
| You can feel electric effects on your body. | You cannot feel magnetic effects on your body |
| Electric field lines of two equal or opposite charges look similar to the magnetic field lines of two equal or opposite poles | Electric field lines of two equal or opposite charges look similar to the magnetic field lines of two equal or opposite poles |
| Electric field lines always start somewhere | Magnetic field lines are always closed (no beginning and no end) |
| The Earth does not seem to have a single, coherent e-field | The Earth clearly has a magnetic field |
| The electric field lines always radiate out from the source. | The magnetic field lines do not radiate out of the source. On the contrary they wrap around the source. |
| The sources of electric fields are electrified objects. | The sources of magnetic fields are moving charges. |