2. the flow of charged particles ; can be positive or negative, but usually negative (electrons) through a conducting metal
3. Field lines point away from positive and toward negative charges . An electric field exists in a region in space if a charge placed in that region experiences an electric force. Electric Fields
4. Write this down! Ω (ohm) A (ampere) V (volt) Units R=V/I V is voltage I is current R Resistance I=Q/t Q is charge T is time I Current V = W/Q W is work Q is charge V Electric Potential Difference (a.k.a. voltage) Formula Symbol Quantity
5. Electric Potential Difference (a.k.a. voltage) the change in electric potential energy per unit charge V = W / Q The SI unit of electric potential difference is the volt , named in honor of Alessandro Volta . One volt is the electric potential difference between two points when one joule of work is done in moving one coulomb of charge between the points.
7. Electric current (I) is measured in amperes , in honor of Andre Marie Ampere . One ampere is the flow of one coulomb of charge per second. 1 amp = 1 coulomb per second = 1 C/s I = Q / t
9. Resistance determines the amount of current flow = the ratio of potential difference to current R = V I The SI unit of resistance is the ohm , , named in honor of Georg Simon Ohm . One ohm of resistance is the resistance such that one volt of potential difference is needed to obtain a current of one amp .
10. power = work / time = ( work / charge ) . ( charge / time ) = electric potential difference . current P ( Watts ) = V ( Volts ) . I ( Amps )
11. Ohm’s Law The ratio of potential difference to current is constant. If R = V/I is a constant value for a given resistor, then that resistor is said to obey Ohm’s Law.
12. Kirchhoff’s Rules Loop Rule: The sum of the potential differences (voltage) around any closed circuit loop is zero.
