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I was trying to find out the cause behind the Explosion at petrol pump due to the Mobile phones but eventually it turns out it is not Radio Frequency which may cause the explosion rather it is totally the static electricity which may cause serious explosion and ignition of vapors, The other reason I found is, due to the spark by the mobile phone battery in case the mobile has fallen out of your pocket and it seems more legit. The second scenario, Its been said that Electromagnetic Waves absorb in liquid across a wide wavelength , is there any possibility that the absorption of radio Frequency in Petrol may cause any explosion ?

My question is, anything can produce Static electricity then why mobile phones are prohibited ? Do they produce more Static Electricity than other equipments ?

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3 Answers

up vote 4 down vote accepted

There's absolutely no danger from the electromagnetic waves coming from the phone. They are nowhere near powerful enough to heat up the gasoline, much less cause it to explode. They also don't produce more static electricity than anything else.

If there's any part of the phone that's hypothetically "dangerous", it might be the battery, as you say. If the battery happens to fall out, and land precisely (terminals-first) onto a conductive surface, it can create a tiny spark which can ignite the vapors.

There's much more danger from the static electricity from your own body when handling the gas nozzle. The best practice should be to lay one hand onto your car, then pick up the nozzle with the other hand and insert it into your tank. (The same when removing the nozzle)

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your answer is quiet satisfying, btw how much power may cause to explode the gasoline and how much power RF frequency may produce ? I have some basic knowledge about RF frequency , and i know there are two different ranges for mobile frequency, 900MHz and 1800MHz , what would be the effect of both on heating up the gasoline ? –  Sufiyan Ghori Jul 11 '12 at 18:47
    
Those frequencies pass right through a fluid like gasoline (they were specifically chosen to pass through as many materials as possible). But that's not the point: the power of the transmissions is what matters: a cell phone uses about 1 watt of power at the most. Compare that to a microwave oven (similar frequencies), which uses 1000 watts. Therefore, the radiation output of a cell phone is practically negligible when considering heating of materials. –  Dmitry Brant Jul 11 '12 at 20:37
    
For additional comparison, sunlight on earth has an intensity of about 270 watts per m^2 (perpendicular to incoming angle). A cell phone transmitter broadcasting at a power of 1W has this intensity at a distance of about 1.7cm. It's not like gasoline/petrol will ignite if sunlight shines through it. You might be able to cause a fire if you soaked your phone in the stuff, but I wouldn't recommend trying that for obvious reasons. –  Wug Jul 16 '12 at 16:22
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They're prohibited because of sensationalism. It's a classic case of something happening, some hasty person drawing a hasty correlation, then hasty action being taken with no regard to whether or not the correlation holds up against logic.

They're better off banning wool socks.

Cell phones don't produce any more static electricity than a more 'typical' device. Remember also that static electricity tends to ruin electronics. It wouldn't make sense for them to generate large amounts of it.

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As others have already mentioned, RF cannot do it, and static is not unique to phones.

One possible cause of sparks is the phone's vibrator. It is essentially a little electric motor with an unbalanced weight attached to the shaft. Like any motor it may generate sparks that could ignite gasoline. See for example http://pocketnow.com/thought/how-does-a-cell-phone-vibrate

I consider it extremely unlikely to cause problems, but it's possible.

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but the phone doesn't vibrate while you're talking ? it vibrates at the time somebody is calling, Petrol pump suggest not to talk on the phone, they doesn't suggest to switch them off. ? –  Sufiyan Ghori Jul 12 '12 at 11:34
    
The vibrator is the only danger I can think of. Talking will not cause any problems, as others have already explained. –  hdhondt Jul 16 '12 at 0:33
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