Part 3

 The electric field can push AND pull charges  Because there are two types of charges (+ and -)  The gravitational field can only pull  Only positive masses

 Charges cause an electrical field.  Each charge creates its own electric field in the surrounding space.  Electric Field is a vector quantity  Has magnitude and direction  Use Electric Field lines(lines of force) to show the Electric Field

 Electric field direction from charge that creates the field:  Away from positive charge  Toward negative charges  The lines begin on positive charges and end on negative charges.  Draw lines perpendicular to charge  Lines never cross

 Electric field strength:  The closer to the charge, the stronger the field  The closer the field lines, the stronger the field  The farther away, the weaker the field

 Electric field strength:  The number of lines are proportional to strength  The more lines the stronger the field

 Electric field strength: (quantitative) E = kq/d 2 ▪ Depends on Charge and distance  E = Electric field strength (Newton/Coulomb, N/C)  k = 9.0 x 10 9 Nm 2 /C  q= charge causing the field (Coulomb, C)  d or r = distance (meters, m)

 A fly accumulates 3.0 x C of positive charge as it flies through the air. What is the magnitude and direction of the electric field at a location 2.0 cm away from the fly? q = 3.0 x C d or r = 2.0 cm = _____ m E = ? equation E = kq/ r2 E = (9.0 x 10 9 )(3.0x ) (0.020) 2 E = 6750 N/C 0.020

Electric Field = force exerted on positive charge If +q = force in same direction (pull) of the field If -q = force in opposite direction (push) of the field

 The strength of the electric field… E = F/q  E = strength of the field (Newton/Coulomb, N/C)  F = Force exerted on charge in field (Newton, N)  q = charge (Coulomb, C) that sits in the field; experiences the force

A charge of -2.0 x   C is placed in a uniform electric field of strength 5000 N/C that points downward. What is the magnitude and direction of the force experienced by this charge?

E = F / q 5000 N/C= F / (-2.0 x C) (-2x10 -6 )(5000)=F -0.01N=F magnitude of the force direction? - 2 charge, the force on the electron is opposite the field! A charge of -2.0 x   C is placed in a uniform electric field of strength 5000 N/C that points downward. What is the magnitude and direction of the force experienced by this charge?