KnowHOW team explains: Although the chances are extremely slim, your mobile phone can generate sparks that can ignite petrol, diesel or liquefied petroleum (or natural) gas. Theoretically, the batteries used in cellphones ? or, for that matter, batteries in most battery-operated devices ?can deliver enough power to start a fire. And the ringer in cellphones uses more than 100 volts for excitation.

There is also a risk of the radio frequency signal inducing a current in any metal that may be nearby, because a mobile phone emits a 5-watt signal. This really can start a fire igniting fuel vapour.

However, such fires can only start if you get close to an oil spill or an open tanker and your phone starts ringing. In other words, the chances are so remote that it?s hardly a risk. Still, cellular operators as well as petrol pump owners issue warnings to avoid litigations in case there is a fire and they are blamed.

Although there have been rumours about petrol pump fires in Australia, Indonesia and the US it has never been conclusively proved that cellphones were the culprit. In fact, the risk of fire from discharge of static electricity ? from your dry hair or sweater ? is far higher than catching a fire from a cellphone.

The question was sent by Arun Kumar Sharma from Ranchi