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I am just confirming here how the concept of electrostatic shielding helps in preventing lightining to be not getting into the car inside .

So we know car has a metal body outside , so first consider there is no lightning happening outside so the outer surface has no charge at all of car body . And the whole metal body is in electrostatic condition , now suppose lightning starts happening that will try to enter the metal body but it doesnt do so.

  • My question is as its a moving phase of lightning from outside in very short time and also charges outside is now making a new distribution how does this all comes under the electrostatic conditons , as in only then only the electric field is supposed to be zero hence the electrostatic shielding effect? Here the the charge distribution outside metal body is not fixed it changes with time so its not electrostatic that i meant .
  • And also by lightning what we meant when we say its doesnt get inside , does it mean the electricfied particles in air? Or electric field which is formed by cloud charged particles which doesnt comes inside?
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    $\begingroup$ Of course, lightning is far from being electrostatic. It is a large pulse of cure trying to get to ground. The biggest help for you in the car is the rubber tires - no path to ground so the lightning goes elsewhere… $\endgroup$
    – Jon Custer
    Commented Jun 29, 2022 at 15:17
  • $\begingroup$ Oh so then why we give this example in electrostatic shielding @JonCuster $\endgroup$
    – Paracetamol
    Commented Jun 29, 2022 at 16:42
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    $\begingroup$ Because the authors don’t understand pulsed power… $\endgroup$
    – Jon Custer
    Commented Jun 29, 2022 at 18:25
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    $\begingroup$ "Understading how the lightning gets prevented from coming inside the car if the conditon is not fully electrostatic in my opinion." What does this even mean? $\endgroup$
    – hft
    Commented Jun 30, 2022 at 0:36
  • $\begingroup$ Oh sorry for my bad wording , i will change it for better one $\endgroup$
    – Paracetamol
    Commented Jun 30, 2022 at 3:57

2 Answers 2

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The situation is nearly electrostatic/magnetostatic because the car is small compared to the lightning bolt. A pulse of lightning gathers its energy from a field that is kilometers in extent. At the speed of light, this takes microseconds. A representative model of lightning surges commonly used by electrical engineers is the 8/20 µs pulse, with an 8 µs rise and a 20 µs decay to half current.

On the other hand, the speed of light delay across a car is only a few nanoseconds. This is the time it takes for charge to respond to the external electric field and for current to respond to the external magnetic field. Thus, the electric and and magnetic fields in the interior of the car are greatly reduced relative to the exterior.

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  • $\begingroup$ Yeah so there can be electric field slightly inside right ? Due to combined effects of lightning and the gravity ? But that is not much for causing any harm to a person sitting inside $\endgroup$
    – Paracetamol
    Commented Jun 30, 2022 at 4:01
  • $\begingroup$ @Paracetamol The car body isn't a perfect conductor and doesn't completely cover the interior, so some energy gets inside. Gravity is not involved. $\endgroup$
    – John Doty
    Commented Jun 30, 2022 at 12:50
  • $\begingroup$ Oh i read in purcell that gravity too needed to be taken into account since charge have mass too so the forces on it needs to be balanced properly $\endgroup$
    – Paracetamol
    Commented Jun 30, 2022 at 21:11
  • $\begingroup$ @Paracetamol The electrostatic force on an electron in a field of a few hundred kilovolts/meter is about 10^16 times the force of Earth gravity on the electron. Gravity may be neglected here. $\endgroup$
    – John Doty
    Commented Jun 30, 2022 at 21:23
  • $\begingroup$ Oh hmm fine thanks $\endgroup$
    – Paracetamol
    Commented Jun 30, 2022 at 21:52
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lightning is an electrical current. this means it consists of an electrical carrier, carrying the electrical charge through a path. this path, starts from a highly charged cloud, and ends in the earth soil, for it has the least possible voltage. everything in nature, if not manipulated by an ulterior force, takes the path of least resistance. we know lightning passes through air, which has a very large resistivity. the moment the lightning hits the unlucky car, the metal conductive body of car makes a very clear path for current towards the downside of the car and the ground. it is not that the metal "shields" you from the lightning. it is more like the metal is an easier target for lightning than the air inside the car. and hence the driver's body.

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  • $\begingroup$ I understood most just the last thing i didnt get , "hence the drivers body" ?? You mean the lightining takes the metal body for conduction and leave the drivers body because least resistant to flowing current is the metal body ,hence he/she is safe ? $\endgroup$
    – Paracetamol
    Commented Jun 30, 2022 at 4:05
  • $\begingroup$ Yes. that's right. $\endgroup$
    – hmg373
    Commented Jun 30, 2022 at 23:07

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