Title: Facilitator Help Page: Quiz 8-2 -- (Do Not Publish)
Course: Basic Electrical Theory and Wiring (Sandbox) > Section: Module 8: Power

Answers and Explanations

1. Power factor is the ratio of true power divided by the apparent power. It is a unitless number, and it is not efficiency. It occurs when you have positive current and negative voltage or vice versa. The moment when you have positive current and negative voltage you get " - power". Thus, this negative power subtracts from your total usable power, which means that you have less power to power your device. However, the power company has to provide the apparent power.
2. Induction Motors
3. I will accept either of these answers:
  1. No - Power factor is caused by alternating current that gets out of phase with the voltage. (This is the way that I look at it. Thus, the power equations are AC = V x I x PF and DC = V x I.
  2. Yes - The power factor is 1 all the time. (For this one, the equation is always the same as V x I x PF. It doesn't make sense to me to keep multiplying by 1 since the actual effect doesn't exist.)
4. \(P\:=\:V\:\ast\:I\:\ast\:PF\:=\:12\:\ast2\:\ast0.85\:=\:20.4\)

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