Halt! This science fiction image shows a human hand surrounded by a green force field. It’s supposed to represent an electric field generated by a hand. What is an electric field? Read on to find out.
What Is an Electric Field?
An electric field is a space around a charged particle where the particle exerts electric force on other charged particles. Because of their force fields, charged particles can exert force on each other without actually touching. Electric fields are generally represented by arrows, as you can see in the Figure below. The arrows show the direction of electric force around a positive particle and a negative particle. For an animated diagram, go to this URL: http://ocw.mit.edu/ans7870/8/8.02T/f04/visualizations/electrostatics/15-CreateField/CreateField_640.mpg
Interacting Electric Fields
When charged particles are close enough to exert force on each other, their electric fields interact. This is illustrated in the Figure below. The lines of force bend together when particles with different charges attract each other. The lines bend apart when particles with like charges repel each other. At the following URL, play “Electric Field of Dreams” to experience interacting fields of two or more charged particles. http://www.cabrillo.edu/~jmccullough/Physics/Electric_Forces_Fields.html
Note: +q = positive charge and –q = negative charge
Q: What would the lines of force look like around two negative particles?
A: They would look like the lines around two positive particles, except the arrows would point toward, rather than away from, the negative particles.
- An electric field is a space surrounding a charged particle where the particle exerts electric force.
- When charged particles are close enough to exert force on each other, their electric fields interact. Particles with opposite charges attract each other. Particles with like charges repel each other.
Explore the big question, "Are force fields real?" with the following interactive simulation at the link below. Then write a brief answer to the big question based on what you learn.
- What is an electric field?
- Create a sketch showing how the electric fields of two negatively charged particles interact.