Question #b9556

2 Answers
Dwight
Jan 14, 2017

#P=I*V = (0.400 A)(12.0 V) = 4.80# watts

Explanation:

Withe the information you have, you could also use

#P=I^2R# or #P=V^2/R#

all will yield the same result.

Roy E.
Jan 14, 2017

#4.8 W#

Explanation:

#P=V xx I# where #V=12.0# and #I=0.400#. #12.0 xx 0.400=4.8#.
You could also have said that #P=V^2/R# giving #12^2/30=4.8#.
Also the question is slightly over-specified, in that you could have deduced the current (assuming that the resistor obey's Ohm's Law) from #I=V/R=12/30=0.4#

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