ELECTRIC FIELDS

What Are Electric Fields?

An electric field is the area around a charge (either positive or negative) that is used to show electrical forces generated by that charge

Electric fields are shown as arrows originating with the charge

The direction of the arrow is given by what a positive test charge would do if dropped within the electric field of the charge

Pictures of Electric Fields

How To Calculate Electric Field Strength Electric field strength (E) can be

calculated with the equation:

E = F/q E: Electric Field (N/C) F: Force felt by the charge (from

Coulomb’s Law) q: Charge of the object

Magnetism and Electric Fields Electricity and Magnetism are

extremely closely related. So much so that they often follow the same equations.

Magnetic field lines follow the same pattern as electric fields

Before we get into “B Fields”, we need to first understand the magnet…

The Simple Bar Magnet

All magnets are made of two halves, or “poles”: north and south

North and south attract each other, just like positive and negative particles!

A north and a south can never be separated: if you break a magnet in half you will always have a north and a south, all the way down to a microscopic level!

How Do Magnetic Field Lines Look? Magnetic Field lines, called “B Field

lines, look identical to electric field lines. The north pole of the magnet acts as a

positive charge, and the south acts as a negative

What Happens When We Put Magnets Together?

Earth and Magnets

The earth has its own magnetic field, generated by its rotation.

The North Pole (geographic north) of the earth acts as a south pole magnet (magnetic south), and the South Pole (geographic south) of the earth acts as a north pole magnet (magnetic north).

This explains why the north needle on a compass is attracted to the North Pole!

Video

Electric Field Video Electric Field Problem Walkthrough Vi

deo

Simulations

Electric Field Hockey B Field Simulator

Picture Credits

Slide 3: downloadanswer.com Slide 4: facstaff.gpc.edu Slide 4: mcat-review.org Slide 7: newsouthwales.inetgiant.com.au Slide 7:scienceblogs.com Slide 8: facstaff.gpc.edu Slide 9: ehow.com Slide 9: sciencephoto.com Slide 11: tigon2008.multiply.com