How long will a device drawing 8 mA last on a 12 v bat that has a 25mAh?
25/8 = 3.125 hours?
You got it.
is there a bat as small as a watch bat that can produce that much mAh at 12v?
Not that I know of.
what is ur mAH for watch bat?
Hell if I know, but I've never seen a 12V watch battery. Most battery chemistries in use today are 1.5 volts or so -- they'd have to pack 8 cells into that watch battery package to get 12V, and I don't think it's been done.
Electrical current and pressure
Voltage is electrical pressure, and it is analogous to water pressure. We don't need to know what the voltage is to answer this; we just need to know that it is considered consistent throughout the problem. The question should be stated as:How long will a device drawing 8 mA at a particular given voltage last on a battery that has a capacity of 25mAh at the same given voltage?.
Yes, if the question is stated as I corrected above.
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