18.1. Electric Current and Circuits http://www.ck12.org
Practice
Questions
The following video covers electric current. Use this resource to answer the questions that follow.
http://www.youtube.com/watch?v=YNtQFSMjWLY
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/64747- What type of current is described in this video (electron or conventional)?
- What drives the current through the circuit?
- What inhibits the flow of current in the circuit?
The following link provides instructional material, example problems, and a quiz on electric current: http://library.t
hinkquest.org/10796/ch13/ch13.htm
Review
Questions
- The current through a light bulb connected across the terminals of a 120 V outlet is 0.50 A. At what rate does
the bulb convert electric energy to light? - A 12.0 V battery causes a current of 2.0 A to flow through a lamp. What is the power used by the lamp?
- What current flows through a 100. W light bulb connected to a 120. V outlet?
- The current through a motor is 210 A. If a battery keeps a 12.0 V potential difference across the motor, what
electric energy is delivered to the motor in 10.0 s?
- electric current:A measure of the amount of electrical charge transferred per unit time. It represents the flow
of electrons through a conductive material or, in the case of conventional current, the flow of positive holes
through a conductive material. - conventional current:In a majority of electric currents, the moving charges are negative electrons. However,
due to historical reasons dating back to Ben Franklin, we say that conventional current flows in the direction
positive charges would move. Although inconvenient, it’s fairly easy to keep straight if you just remember
that the actual moving charges, the electrons, flow in a direction opposite that of the electric current. - resistance:Defined as the ability of a substance to prevent or resist the flow of electrical current.
- ampere:Using the SI definitions for the conventional values, the ampere can be defined as exactly 6. 241 ×
1018 elementary charges per second or 1.00 coulomb of charge per second.