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I have a question in my mind. What if I keep holding a Duracell(1.5V Battery) touching both the terminals with my fingertips? Will the circuit be completed and the battery drain? Or will it have no effect? Why?

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  • $\begingroup$ The battery will drain anyway. They don't last forever, even in the package. I suppose you want to know if it will drain faster than that? $\endgroup$ – Brick Oct 15 '19 at 18:27
  • $\begingroup$ Yes, Brick. But why doesn't the cell get hot. Like, if we connect a wire directly across the terminals, the cell gets hot. Why doesn't it happen so in this case? $\endgroup$ – Aayush Aggarwal Oct 15 '19 at 18:29
  • $\begingroup$ FYI: Long-term exposure to small D.C. currents can be harmful to your body tissues. Do not go to sleep with that battery taped to your hand. $\endgroup$ – Solomon Slow Oct 15 '19 at 19:18
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You have to consider the electrical resistance of your fingers. This Aricle shows that the human body has a resistance of up to 100,000 ohms. Air has a resistance of about 2 x 10^16 ohms. While a very long thick wire has a resistance of 4 ohms. So, it looks like your fingers would indeed conduct electricity faster than air, but you'd have to hold the battery for a REALLY long time before you drain it.

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    $\begingroup$ Re, "the human body has a resistance of 100,000 ohms." That is not what the article says at all. It says that if you attempt to measure the electrical resistance of a live human, you can get readings as high as 100,000 Ohms, and as low as 500 Ohms depending on where and how the electrodes are attached to the body. $\endgroup$ – Solomon Slow Oct 15 '19 at 19:22
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    $\begingroup$ Re, "A long thick wire has a resistance of 4 Ohms." How long is "long?" How thick is "thick?" The DC resistance of a segment of metal wire will be proportional to the length, and inversely proportional to the cross section. For a thousand feet of #12 copper wire (long enough for you?) it's less than 1.6 Ohms. hyperphysics.phy-astr.gsu.edu/hbase/Tables/wirega.html $\endgroup$ – Solomon Slow Oct 15 '19 at 19:26
  • $\begingroup$ @SolomonSlow yes, you are correct. Also that the resistance figure for a wire is for a 1000 meter long wire. It would be much less than for a 4cm wire. And the resistance of air depends on the humidity of the air. But I was trying to get across in a very simple manner, that a human body is FAR more resistant than a wire, so it would take a long time, but not forever, to drain the battery. $\endgroup$ – foolishmuse Oct 15 '19 at 19:27
  • $\begingroup$ To expand on @SolomonSlow 's comment, resistance is an extensive property, not intensive (i.e. a property on an object, not a substance). The unit here should be Ohm-meters, not Ohms (a substance having 1 Ohm-meter means that resistance in Ohm equals length in m divided by cross-sectional area in m^2). $\endgroup$ – Acccumulation Oct 19 '19 at 0:30

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