Unit 15: Electric Charges – Weeks 9-10

Standard: 5 j*, k*, l*, m*

Electric Charges

Who was Coulomb? (Coulomb’s Law)

Electric Charge, Fields and Force

Electric Potential and Work

The electrostatic mass filter

Van DeGraff Generators

Doctor Frankenstein, grave robbers and the myth of the Reanimators

Electric and Magnetic Phenomena

5. Electric and magnetic phenomena are related and have many practical applications. As a basis for understanding this concept:

a. Students know how to predict the voltage or current in simple direct current (DC) electric circuits constructed from batteries, wires, resistors, and capacitors.

b. Students know how to solve problems involving Ohm’s law.

c. Students know any resistive element in a DC circuit dissipates energy, which heats the resistor. Students can calculate the power (rate of energy dissipation) in any resistive circuit element by using the formula Power = IR (potential difference) _ I (current) = I2R.

d. Students know the properties of transistors and the role of transistors in electric circuits.

e. Students know charged particles are sources of electric fields and are subject to the forces of the electric fields from other charges.

f. Students know magnetic materials and electric currents (moving electric charges) are sources of magnetic fields and are subject to forces arising from the magnetic fields of other sources.

g. Students know how to determine the direction of a magnetic field produced by a current flowing in a straight wire or in a coil.

h. Students know changing magnetic fields produce electric fields, thereby inducing currents in nearby conductors.

i. Students know plasmas, the fourth state of matter, contain ions or free electrons or both and conduct electricity.

j. * Students know electric and magnetic fields contain energy and act as vector force fields.

k. * Students know the force on a charged particle in an electric field is qE, where E is the electric field at the position of the particle and q is the charge of the particle.

l. * Students know how to calculate the electric field resulting from a point charge.

m. * Students know static electric fields have as their source some arrangement of electric charges.

n. * Students know the magnitude of the force on a moving particle (with charge q) in a magnetic field is qvB sin(a), where a is the angle between v and B (v and B are the magnitudes of vectors v and B, respectively), and students use the right-hand rule to find the direction of this force.

o. * Students know how to apply the concepts of electrical and gravitational potential energy to solve problems involving conservation of energy.