- Slides: 8
The Electric Field
The Electric Field •
Electric Fields • Charges organize themselves on a conductor so that the electric field inside the conductor is 0. • So if you put a test charge inside the conductor, the charge will feel no force
The Electric Field • The units of E are Newtons/Coulomb • The electric field for a charge can be drawn with field lines • Positive charges have lines that go away from the center • Negative charges have lines that go into the center
The Electric Field • The Van de Graaff machine brings ions to the top at the metal dome by scraping them off the belt with a metal comb. • Putting your hand on it when it starts will give you that same charge. The charge goes into your hair, making it follow electric field lines. Your hair repels each other and straightens out.
The Electric Field • Example 1: A positive test charge of 4. 0 x 10^(-5) C is placed in an electric field. The force acting on it is 0. 60 N at 10°. What is the magnitude and direction of the electric field at the location of the test charge? Does the direction matter?
The Electric Field • Example 2: You are probing the field of a charge of unknown magnitude and sign. You first map the field with a 1. 0 x 10^(-6) C test charge, then repeat your work with a 2. 0 x 10^-6 C test charge. a. Would you measure the same forces with the two test charges? Explain. b. Would you find the same fields? Explain.
Electric Potential Energy • Homework! Due 4/11 pg 420 #1 -4 and pg 426 #1 -3 • EXTRA CREDIT pg 420 #5