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Voltage, Current, and Resistance
11 questions By Tony R. Kuphaldt
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Question 10 of 11
Suppose a battery outputs a voltage of 9 volts. Using algebra, calculate how many joules of energy are imparted to every individual electron moving through this battery.
Reveal answerFor a 9 volt battery, there will be 1.44 ×10−18 joules of energy imparted to each electron moving through it.
Notes:This problem is another exercise in using scientific notation, and requires that students put concepts together that were learned previously.
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Question 11 of 11
What is the difference between DC and AC electricity?
Reveal answerDC is an acronym meaning Direct Current: that is, electrical current that moves in one direction only. AC is an acronym meaning Alternating Current: that is, electrical current that periodically reverses direction (“alternates”).
It is important to realize that “DC” and “AC” may also be used to represent voltage as well as current. That is, it is possible to have a voltage that alternates back and forth in polarity (“AC” voltage) just as it is possible to have a current that alternates back and forth in direction of motion.
Notes:Though it may seem oxymoronic to refer to either “DC” or “AC” voltage (Direct Current voltage, or Alternating Current voltage - “current voltage”?), the usage of these acronyms as such is commonplace.
I’m having trouble with combo circuits
I can understand that voltage is potential energy to move an electron between two points and that something like a battery stores this potential independently of current flow. However, if Ohm’s Law states that V=IR and anything multiplied by zero is zero then V=0x has to be V=0. No current, no voltage. How to reconcile this seeming paradox?