7A
YOUR ANSWER: 25 watts.
Right. P is still equal to E x I.
What is the power consumption in the circuit?
10 watts.
frame 9A
100 watts.
frame 6C
7B
YOUR ANSWER: P = E x I.
Well, at least you remembered the basic power formula.
But you were asked, which formula you would use to solve for power, if voltage and
resistance of the circuit were known.
We just gave you the formula on the preceding page: P = E2
R
Here is an explanation as to how we arrive at this formula. P = E x I in our basic power
formula. I = E in Ohm's law. We car, substitute E for "I" in the basic power
R
R
law; thus, P = E x F or P =E2.
R
R
Now, go back to frame 9A and select the correct answer.
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