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.

 

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