Since we use AC for domestic purpose, shouldn't Back EMF (Counter-EMF) be produced in household wires? If yes, then the output voltage in the appliances will be less (that's what my stupid brain says! ). But this does not happen in our houses because we don't see bulbs glowing with low intensity (or does it?). Can sombody explain this?
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In theory you are right. The wires indeed produce a counter-EMF. But let's get some concrete numbers. The inductive reactance of a wire is $$X_L = 2\pi f L \tag{1}$$ where $f$ is the frequency of the AC power grid, and $L$ is the inductance of the wire.
The frequency $f$ is quite small on purpose: $50$ Hz or $60$ Hz (depending on the country in which you live). And the inductance of a straight wire is very small: typically a few $10^{-6}$ Henry per meter.
Thus, according to equation (1) you get an inductive reactance of typically a few $10^{-4}$ Ohm per meter. This is completely neglectable when compared to the resistance of a light bulb (typically some $100$ Ohm).
You also see: This situation would change to the worse
- if the AC power grid would operate in the high frequency range (for example with $f=10$ MHz instead of $50$ Hz),
- or if you would replace a piece of the straight wire by a coil with a large inductance (for example $L=1$ Henry).
answered Sep 30, 2021 at 10:44
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$\begingroup$ ...or if you got a nanosecond-long flash from an orbital EMP, frying everything electronic connected to the power grid (being on a generator won't provide much isolation either) $\endgroup$– lurscherCommented Sep 30, 2021 at 20:45