Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: islador on 21/02/2010 22:09:13

Title: How long can the human body resist a 2000 V shock?
Post by: islador on 21/02/2010 22:09:13

What Would HAPPENED IF your human body being shocked with 2000 volt and how long can any human resist till he/she faints ? like how many seconds/minutes can he resist till fainting and before dieing or how many volt can he resist before fainting and dieing ? please answer




Mod edit - Please could you make the subject a question?  Thanks.

Title: How long can the human body resist a 2000 V shock?
Post by: chris on 23/02/2010 13:43:21

The voltage is not the significant factor; it is the current that determines the lethality of a shock. If you are hit with a taser, a stun gun or you touch the spark plugs in an engine that is running (voltage circa 35-50,000) this will hurt and feel unpleasant, but the current will be so low as to render the shock generally harmless.

To put this into context, the shock you get when you step out of a car and touch the body work on a hot day, or after walking around on some floor coverings wearing rubber-soled shoes, will probably exceed 2000 volts. This has never been directly fatal to anyone, to my knowledge.

Chris

Title: How long can the human body resist a 2000 V shock?
Post by: Bored chemist on 23/02/2010 22:12:24

Voltage and current are not independent. They are related by Ohm's law ( or approximations to it for non-linear systems)
You can't have one without the other.
If you measure the peak current from a "static" spark you will find it's large. The point is that it doesn't last long.
The lethality  is a complicated combination of energy dissipated, the time scale over which it takes place and where in the body the current flows.

Title: How long can the human body resist a 2000 V shock?
Post by: Geezer on 23/02/2010 22:43:22

Quote from: Bored chemist on 23/02/2010 22:12:24

Voltage and current are not independent. They are related by Ohm's law ( or approximations to it for non-linear systems)
You can't have one without the other.
If you measure the peak current from a "static" spark you will find it's large. The point is that it doesn't last long.
The lethality  is a complicated combination of energy dissipated, the time scale over which it takes place and where in the body the current flows.

BC is quite correct. The reason some high voltages are not lethal is because they are either very brief (like a static discharge spark for example), or the current is limited by an impedance (typically a resistance), or usually a combination of the two.

The impedance might be in the source (like the resistance in spark plug wires for example), or it can be in the human body, and the human body resistance can vary significantly depending on lots of factors. So, under certain circumstances, you might survive 2,000 volts, or even much more. Under a different set of circumstances, 100 volts could prove fatal.

Title: How long can the human body resist a 2000 V shock?
Post by: islador on 24/02/2010 01:44:59

So you mean that there is a harmless sparks i mean that there is electricity with high voltage but harmless ?