- #1
waqarrashid33
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Which shock will be most dangerous for human
1.High Voltage and low current
or
2.High current and low voltage
1.High Voltage and low current
or
2.High current and low voltage
BruceW said:So if I include the internal resistance of the voltage source, then:
[tex] V - I R_{internal} = IR [/tex]
So the voltage (through me) is not as great as it should be at very high currents.
And this is just for D.C. right?
boneh3ad said:So in light of all this, if you had an AC power system running at, say, 5 kVo-p and 5kHz with roughly 100 mA running through it under normal operation, how bad would that be to get your finger too close to one of the leads? I ask because I did that and was wondering how much I lucked out.
BruceW said:I never really understood this. V=IR, and the resistance is defined by the material the person is made out of, so surely the ratio of current to voltage is fixed?
256bits said:Interesting.
Would anyone know how much of the voltage is "consumed" by the spark gap versus what is left over for the zap to the finger?
BruceW said:So am I right in thinking that the danger to a human is due to the true current which flows through their heart/brain/muscles? And that this true current isn't necessarily given by Ohm's law?
1. low voltage & low current: safe (think small batteries)
2. high voltage & low current: safe (think Van de Graaff)
3. low voltage & high current: unsafe (think arc welders)
4. high voltage & high current: very unsafe (think power lines, lightning)
A "high electric field" would produce a high voltage. Voltage is simply a measure of the difference in electric potential between two points.What about high electric fields? Can we look at electric fields instead of voltages?
Sunlight is composed of photons. Each photon can only excite an individual particle to a certain amount depending on the frequency. Most of them simply cause heat to be generated, nothing else.The electric field from the sun's light is around 600 V/m using Poynting flux (1 kw/m2 sunlight intensity). Why isn't this deadly?
The resistance of the skin is finite and whether in a DC current or AC current it usually only matters what the voltage is. Extremely high frequencies may act slightly different, but I wouldn't go putting my hand on something exposed at that frequency.Also, I'm a little bit confused. For high frequencies, objects become poor conductors, so the electric fields should penetrate the skin. For low frequencies, such as AC mains power, objects become good conductors, so there shouldn't be penetration of the skin.
Can't we view the electric field of a power line as pointing downwards from the hot wire to the ground, and traveling in the direction of the power lines with 60 hz frequency (i.e., a transmission line)? Are the free electrons in humans standing under a power line rearranging to create zero field in the person, or should a person be treated as a dielectric instead and worry about polarization current? I imagine at high frequencies the polarization current can get really large.
Drakkith said:A "high electric field" would produce a high voltage. Voltage is simply a measure of the difference in electric potential between two points.
Sunlight is composed of photons. Each photon can only excite an individual particle to a certain amount depending on the frequency. Most of them simply cause heat to be generated, nothing else.
The resistance of the skin is finite and whether in a DC current or AC current it usually only matters what the voltage is. Extremely high frequencies may act slightly different, but I wouldn't go putting my hand on something exposed at that frequency.
A power line isn't charged like you might put a charge on an electrode. The voltage goes into causing a current flow. Unless you touch the exposed wire there won't be a potential difference because of the huge resistance of the dielectric surrounding the cable and because of the air.
Generally, high voltage and low current is considered more dangerous because it can cause electrical burns and tissue damage, while low voltage and high current can cause muscle contractions and involuntary movements.
High voltage and low current can cause electrical burns, tissue damage, and interference with the body's electrical signals, leading to heart rhythm abnormalities and other health issues.
No, low voltage and high current can still be dangerous and cause muscle contractions, burns, and other injuries if the current is high enough. It is important to always take safety precautions when dealing with electricity.
Yes, high voltage and low current can be lethal, especially if it passes through vital organs or disrupts the heart's electrical signals. It is crucial to seek medical attention immediately if you experience an electric shock.
To protect yourself from high voltage and low current, it is important to follow safety guidelines, such as wearing protective gear, avoiding contact with live wires, and ensuring that all electrical equipment is properly grounded. It is also crucial to have a clear understanding of electrical safety and seek professional help when dealing with high voltage equipment.