Electric Currents and Circuits

Good Evening Parents and Students,

We will end our investigation of electricity with our 20Q Summative Assessment this Friday March 31, 2017. If you have not submitted a 20Q practice quiz two times make sure you do before Friday when your block begins.

At this point of this chunk's learning experiences you have engaged in you should be able to answer the following questions: (You can find the answers to these questions on Schoology, click on the "Review Sheets Folder" then click on "Electric Currents and Circuits Review sheet".

Questions:

A.What are the units for electrical potential or potential difference? What are the units for electric current? What are the units for electrical resistance? B.Define electric current. What is the cause of an electric current? C.Compare the motion of the electrons to the motion of electric charge in a closed electric circuit. D.Give at least two examples of a voltage source. E.What 3 factors determine the electrical resistance of a material? F.True or false and explain: “the source of electrons in a circuit is the voltage source” G. If electrons flow very slowly through a circuit, why does it not take a noticeably long time for a lamp to glow when you turn on a distant switch? H. If the voltage impressed across a circuit is held constant while the resistance doubles, what change occurs in the current?(2) If the resistance of a circuit remains constant while the voltage across the circuit decreases to half its former value, what change occurs in the current? I. Will the current in a light bulb connected to a 220 V source be greater or less than when the same bulb is connected to a 110 V source? J. In a circuit of two lamps in series, if the current through one lamp is 1 A, what is the current through the other lamp? Defend your answer. K. If 6 V are impressed across the above circuit and the voltage across the first lamp is 2 V. what is the voltage across the second lamp? Defend your answer. L.In a circuit of two lamps in parallel, if there are 6 V across one lamp. What is the voltage across the other lamp? M. How does the sum of the currents though the branches of a simple parallel circuit compare to the current that flows through the voltage source? N.To connect a pair of resistors so their equivalent resistance will be more than the resistance of either one, should you connect them in series or in parallel? (2) To connect a pair of resistors so their equivalent resistance will be less than the resistance of either one, should you connect them in series or in parallel?

Thank You,

Ms. Bolton