It depends on the radius. It is estimated that a discharge of 50,000 amperes, for example, is already harmless to a bather 125 m from the point of incidence. The current intensity decreases as the inverse of the square of the distance. So, with twice the distance, it drops to 1/4. With triple, it drops to 1/9. And so on. That’s why, when lightning strikes in Copacabana, someone in Ipanema doesn’t die from electrocution. Lightning behaves the same way at sea or on land. The difference is that, as the current always tries to concentrate in the most conductive medium, in the open sea it is divided equally between our body and the water. Already on land, she always focuses on our body – and there the damage is greater.
electrifying diving
Check out the consequences of a 50,000 amp beam at different distances
Certain death
A person swimming up to 50 m from the point of incidence of the electrical discharge would suffer a shock of more than 300 mA (milliamps). Result: a massive heart attack
chance of survival
Between 50 m and 85 m, the electrical discharge decreases, varying between 300 and 100 mA. The swimmer would suffer burns, asphyxiation and, in some cases, cardiac arrest, but could be saved.
reduced risk
Between 85 m and 125 m, the intensity is between 100 and 50 mA. It’s not enough to kill anyone, but only because the electrical discharge of lightning lasts for a short time – about a millisecond. A longer-lasting discharge at the same intensity, as in the shock of a shower, could indeed kill
Safe and sound
Above 125 m from where the lightning struck, a person in the sea would receive an electrical discharge of less than 50 mA. She would feel the typical tingling, but no risks.
ATTENTION!
These values are only representative. ME advises: during a thunderstorm, always get out of the water and find a safe place
• Lightning is atmospheric electrical discharge. Lightning is the light and thunder is the sound caused by the ionization of the air and the shock with the electrical charges of the clouds
Source Dulcidio Braz Jr, professor of physics at Anglo and author of the blog “Física na Veia!”, and Silverio Visacro Filho, professor of Electrical Engineering at the Federal University of Minas Gerais (UFMG)
Read too:
– What happens to someone who is struck by lightning?
– How does lightning occur?
– Can lightning energy be harnessed?