Brain Teasers
Hair Raising Duffus
Duffus Mcklutski was not the most suave debonair guy. He was a cross between Grizzly Adams and the local garbage collector. So when the girl next door remarked that he was kind of cute in a bushman sanitation worker kind of way, but would look better with curly hair and a bath, Duffus wasted no time in arranging his makeover. Not sure how he would curl his hair he started with his yearly bath. But since it had been so long since last he bathed, he had no towels in the bathroom to dry himself off. So Duffus, in a pair of shorts dripping wet, wandered out to his tool shed to see if he could do anything about his straight hair dilemma. "Hmmm, weedwacker" he muttered as he turned on the 15000v neon transformers which power the neon lights in his shed. But not watching what he was doing, he touched an open end of the transformer and still being more than damp, he was zapped with 15000 volts of electricity. Duffus was unharmed however and achieved a slight curl to his hair.
But why was Duffus almost unaffected by the 15000v shock?
But why was Duffus almost unaffected by the 15000v shock?
Hint
It has to do with electrical properties and neon specifically.Answer
Neon transformers have very high voltage, but almost no amperage. In fact, they rated in milliamps or thousandths of an amp. Like a cattle prod, it gives a jolt but won't kill. Where as if the amperage were high and voltage lower as in some welding equipment, Duffus would most surely not have been so lucky. Neon sign installers are often zapped yet rarely injured. The other reason is that the frequency of the transformers is different from household power allowing the electricity to travel over the skin, especially wet skin, rather than through the body.Hide Hint Show Hint Hide Answer Show Answer
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Comments
I like the way u tell these humourous stories. How many Duffis stories do you have?
Shockingly good one. Is there a Duffus Mcklutski web site?
Not Yet but I may add a page or two to mine someday.
great teaser, i just covered that this year in physics - high voltage sounds scary, which is why its used, but it is not the voltage that matters but the amperage - amps being the current that flows through. (real quick physics lesson - V=IR - volts = amps*resistance. so if you have 15000v but 15000000000ohms (resistance) then you have only 1 millionth of an amp, which is not very serious). awesome teaser
Jul 30, 2005
FYI: Neon sign transformers are quite capable of delivering a fatal shock. 6 mA, or 6/1000 of an ampere, is all that is necessary to drive the heart into fibrillations. Many neon sign transformers are rated upwards of 75 watts, which, via Ohm's law, results in a current of 75/15,000=5 mA,enough to prevent Doofus from letting go. Skin resistance, particularly when wet, can decrease to the range of 100 -1500 ohms, much less than the resistance of a neon tube. Furthermore, the "skin effect" that causes electrons to flow only on the surface of a conductor only occurs at frequencies in the millions of hertz, i.e. radio frequencies. Neon signs operate at 60 Hz, just like every other American appliance (50 Hz if you live in England).
Jul 30, 2005
FYI: Neon sign transformers are quite capable of delivering a fatal shock. 6 mA, or 6/1000 of an ampere, is all that is necessary to drive the heart into fibrillations. Many neon sign transformers are rated upwards of 75 watts, which, via Ohm's law, results in a current of 75/15,000=5 mA,enough to prevent Doofus from letting go. Skin resistance, particularly when wet, can decrease to the range of 100 -1500 ohms, much less than the resistance of a neon tube. Furthermore, the "skin effect" that causes electrons to flow only on the surface of a conductor only occurs at frequencies in the millions of hertz, i.e. radio frequencies. Neon signs operate at 60 Hz, just like every other American appliance (50 Hz if you live in England).
I knew that.
It's Duffus.
It's Duffus.
milliamps aren't millionths of an amp, but thousandths of an amp. And 6 milliamps will cause a heart attack.
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