# Moving while lighting, will be induced current in me?

1. Jan 20, 2008

### Physicsissuef

ometimes people say that if you moving while lighting, there will be current induced in you, and you'll die, is it correct, and if so how the electrical circuit is closed? (They say if lighting strikes near you, from the electrical field, if you move, there will be induced current in you)

Last edited: Jan 20, 2008
2. Jan 20, 2008

### Staff: Mentor

The title and first sentence don't make any sense to me. What does "moving while lightning" mean? Is English your native language?

3. Jan 20, 2008

### dst

What he presumably means is; Will a lightning storm induce, in a person who is moving on the ground, a current sizeable enough to kill them? If so, to where does this current flow?

4. Jan 20, 2008

### Physicsissuef

Yes that's was the point. Thanks for correcting me. Actually the question is: "Will a lightning storm induce, in a person who is moving on the ground, a current? If so, how the electrical circuit will be closed?"
btw-English is not my native language.

Last edited: Jan 20, 2008
5. Jan 21, 2008

### Physicsissuef

Here is some http://img81.imageshack.us/img81/5092/85498790am6.jpg" [Broken]

Last edited by a moderator: May 3, 2017
6. Jan 21, 2008

### TVP45

No. Everyday observation should convince you this is not so.

7. Jan 21, 2008

### NoTime

First, lightning strikes do not last long enough for you to move any significant distance.
However, you don't need to move since the lightning itself is moving charges.
So yes, a current will be induced in nearby objects, like you.
Electrical circuits do not need to be closed, in the sense that you are thinking of, for a current to flow.

8. Jan 21, 2008

### Physicsissuef

Do I must move, so current will be induced, or I can just stand?

9. Jan 21, 2008

### NoTime

You can just stand.

10. Jan 21, 2008

### Physicsissuef

What will happen, if I stand? I mean how the current is induced?

11. Jan 21, 2008

### NoTime

Moving charges (the electrons in the lightning) generate a magnetic field.
The changing magnetic field, as the lightning starts and stops, moves electric charges.
The same principal that the transformer is based on.

12. Jan 21, 2008

### Physicsissuef

Yes, that was my point. But in the transformer there is electrical circuit closed. In the lighting case, there isn't any closed circular loop.

13. Jan 21, 2008

### NoTime

Without a closed circular loop you have potential differences. In some ways you are a battery.

14. Jan 21, 2008

### TVP45

In the normal sense of currents, nearby lightning strikes (say 30 m away) do not induce currents in a human body. There are currents induced in fences and wires which are metallic conductors but not in the body (unless you want to define small dislocations of ions as currents).

15. Jan 22, 2008

### Physicsissuef

If I am close (let's say 10 meters) and the lighting strikes, will current be induced in me from the magnetic field, and how the electrical circuit will be closed?

16. Jan 22, 2008

### TVP45

It would be impossible to answer all the "what-if"s about this situation. In general, you will not see a measurable current in the body. You do not need a closed circuit in order to have a current. And, to be more correct, it is not the current that is induced in such a case, but the voltage.

Is there a point to your question? Perhaps that might be more illuminating.

17. Jan 22, 2008

### Physicsissuef

I do not need a closed circuit in order to have current, please explain me how?

18. Jan 22, 2008

### Integral

Staff Emeritus
A lighting strike creates a very large potential gradient in the earth around it. If you are standing facing the strike then chances are good that your feet will each be on the same equipotential line, and no harm will come your way.

On the other hand if you are standing such that the strike in on your left or right chances are good that your feet will NOT be on equipotential lines and you will be come a conductor. The current path would then be in one leg and out the other, this can cause potentially fatal injuries.

The case of a lighting strike is a good example of when the earth will NOT be at zero potential.

19. Jan 22, 2008

### Physicsissuef

So the earth will gain potential from the lighting? I mean when lighting strikes, the protons are going up, and the electrons down. So in the air high up, there is build of positive charge (+) and on the ground build of negative charge (-), right?

20. Jan 22, 2008

### Integral

Staff Emeritus
Forget about the protons, only electrons need be considered.

21. Jan 22, 2008

### TVP45

Most lightning is what is called negative lightning where the clouds become negatively charged on the bottom and the earth below becomes positively charged. The stroke usually proceeds down from the cloud and, as it nears the earth, a positive streamer may rise to meet it.

A small percentage of lightning is positive where the clouds are positively charged on the bottom and the earth below negatively charged. So-called heat lightning which occurs at a distance from a storm is often this.

Integral makes an excellent point. If you are caught in the open during a lightning storm, it is important to crouch as low as possible with feet together (the bird on a wire low potential trick).

22. Jan 22, 2008

### TVP45

It's easy. Most science students have seen it dozens of times. Many non-science students have seen it numerous times. I'll leave it to you to think about.

23. Mar 29, 2008

### Physicsissuef

Is it possible that I will not get injury, if I am standing on one leg? I can't understand, why while standing I will not get "shock", is it because of the fact that I need to move among magnetic field to induce current in me, like in transformer?