over voltage due to external causes

                      over voltage due to external causes

~ over voltage due to external causes is main reason is lighting stork

~ in the monsoon rain , the electric charge of the promises accumulate due to the atmospheric process.

~ positive pores accumulate in some part or part of it while negative charge accumulate in some clouds.

~ when this argument passes close to the ground the charge induce reverse polarity on earth.

~ when increase the charge in cloud there is increase potential between earth and cloud.

~ these potential range from 5 to 20 million watts or a potential gradient of 5000v to 10000v per centimeter 

~ when breakdown air between cloud and earth and spark the false between earth and cloud.

~ potential gradients are not distribute uniformly.   

~  The middle part of the cloud is higher.

~ the initial flash or streamer is turned from the cloud by a pilot leader that carries the accumulated charge.

~ the pilot leader continues to come down until the potential gradient of the tip is maintained.

~ when the pilot approaches the earth, the electrostatic filed of the earth increases and a streamer is generated from the earth.

~ the result is a heavy spark between the cloud and the earth.

~ this is known as a lighting stroke. 

                                         

                                                        Lighting stork