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Homework Statement
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The question "What is the minimum wattage rating the resistor should have?" comes after a previous problem I did to determine the maximum and minimum current when given a resistors tolerance. Here are all the values from that problem, some aren't really important but want to show all that I have. In the problem I used the Minimum Current as my value for I:
$$ V = 7.0V $$
$$ R = 82 \Omega +/- 5% $$
Max. Resistance = 86 ohms
Min. Resistance = 78 ohms
Minimum Current = 81.4 A
Maximum Current = 89.7 A
Homework Equations
1.$$ P = IV $$
2. $$ P = \frac{V^{2}}{R} $$
3. $$ P = {I^{2}}{R} $$
The Attempt at a Solution
What I'm not sure about if should I use the 1st, 2nd or 3rd equation?
When I used the 1st one I got $$ (81.4 A) \times (7.0 V) = 569 W $$
If I use the 2nd one I get $$ \frac{7.0^{2}}{86} = 569 mW $$
For the third I get: $$ (81.4^2) \times (86) = 569 kW $$
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