Question

At ground why only positive charge is available?in lightning why negative charges accumulated at lower edges?if cloud have a negative charge and ground have a positive charge it attracts the cloud , how is electricity formed?

Answer 1

Hi,

The mechanism by which charge separation happens is still the subject of research.

According to the electrostatic induction hypothesis, charge separation appears to require strong updrafts which carry water droplets upward, super cooling them to between -10 and -20 °C. These collide with ice crystals to form a soft ice-water mixture called graupel. The collisions result in a slight positive charge being transferred to ice crystals and a slight negative charge to the graupel. Updrafts drive the less heavy ice crystals upwards, causing the cloud top to accumulate increasing positive charge. Gravity causes the heavier negatively charged graupel to fall toward the middle and lower portions of the cloud, building up an increasing negative charge. Charge separation and accumulation continue until the electrical potential becomes sufficient to initiate a lightning discharge and thus lightening occur when the distribution of positive and negative charges forms a sufficiently strong electric field.