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The torque on electricity generators is continuously adjusted to keep them running at a constant speed (e.g. 60Hz in the US and 50Hz in the UK). When you turn on some electrical item the current it consumes places a greater load on some electricity generator somewhere and this reduces the speed. To counter this, at the generating station more torque is ...

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Power generation and supply management is not easy and it is to their credit that most of the time power companies supply people with AC at the same voltage no matter what the demand for power is. So when we turn on appliances we do not see the voltage drop as a result. Or more realistically when everyone gets home from work and starts cooking/ boiling ...

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Remember, $\vec{\nabla} \times \vec{B} = \mu_0 \vec{J}$, and $\vec{J}$ will be zero anywhere except on the loop itself, where it will be singular. Do you mean, perhaps, that the line integral around the loop equals the current, a la Ampere's law?

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The first equation is when you want to solve for either the voltage, current, or power already knowing the other two, similar for $P=I^2R$, when you want to solve for an unknown already having knowledge of the other two. The last equation you get by noting that, $P=IV=I^2R$, hence $V=IR$ or $I=\frac{V}{R}$ plugging this into, the first equation you get ...

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Each LED has both a voltage rating and a current rating (100mA). When connected in parallel, they will all receive the voltage of your power supply and draw 100mA each, so the total will be 300mA. When connected in series, they will split the supply voltage between them, so the supply voltage will have to be 3 times the individual LED voltage rating. Each ...

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Your instincts are spot on. While it’s still common for people to refer to electricity and magnetism as different phenomena, they’ve been formally unified since Maxwell’s 1873 paper on the subject, and they were known to be intimately related for decades before that through Faraday’s work among others. “Electromagnetism” covers all of the behavior of ...

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