Ohm's law
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Given that P = 100 W and U = 110 V, find R.Method 1: I = P/U ≈ 0.91 A; R = U/I ≈ 120.9 ohms.
Method 2: R = U²/P = 121 ohms.
Which method is correct? Why is there a gap? Which calculation do we usually use? Thank you!
I = P/U ≈ 0.91, R = U/I ≈ 120.9. For the first case, R = U/I; for the second case, I = P/U. Substitute I=P/U into the previous formula R=U/(P/U)=U squared/P. You didn’t divide properly when calculating, so rounding was done to one decimal place.
The results are more or less the same, with only slight differences in the decimal values; since the formulas used for derivation differ, it’s impossible for the algorithms to be exactly identical, and some deviation is normal