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Self-explanatory question but to add what I know, by this I will also know if I am right or wrong.
I read somewhere that Earth is positively charged, but is not the state (whether positive/negative) of a body relative to the near body/object. If Earth is positively charged, why is it so? Is there any negative charge around it which helps Earth retain it's positive charge?

Also, what happens to charges that flow to the ground ?

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  • \$\begingroup\$ The charge is not relative, it is absolute. Electron is absolutely negative, proton is absolutely positive. If there are more electrons than protons, then it is negatively charged. \$\endgroup\$ – Eugene Sh. Sep 5 '18 at 21:16
  • \$\begingroup\$ @Eugene Sh. Correct, In my question i was stating the charge on a body/object relative, not the charge of electron or photon. \$\endgroup\$ – calculusnoob Sep 5 '18 at 21:19
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    \$\begingroup\$ As I said, the charge on a body is absolute and defined by the majority of the charge carriers on that body.. \$\endgroup\$ – Eugene Sh. Sep 5 '18 at 21:20
  • \$\begingroup\$ @EugeneSh. what if the body is neutral ? And then exposed to either positive or negative, would it acquire the opposite of that charge ? \$\endgroup\$ – calculusnoob Sep 5 '18 at 21:24
  • \$\begingroup\$ What do you mean by "exposed"? Placed in electrical field? Or having a physical contact with? \$\endgroup\$ – Eugene Sh. Sep 5 '18 at 21:26
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If Earth is positively charged, why is it so, is there any negative charge around it which helps Earth retain its positive charge ?

It's actually a little more complicated than that. The earth around you locally is part of a giant circuit!

Thunderstorms generate a negative current which then flows back to the ground wherever there aren't thunderstorms. So it really depends on the weather. It also depends on a variety of other factors like solar storms and ionization of the upper atmosphere, but this gives you an idea of what goes on.

I coudln't find the graph but the local electric field also changes when the sun shines from ionization. The electric field above also contributes charge, thunderstorms and other effects all contribute. All in all, the ground's net charge can be considered zero and a reference for all other charges.

enter image description here Source: https://slideplayer.com/slide/6192933/

Also, what happens to charges that flow to the ground ?

The ground also has conductivity (or functions like a resistor), so it distributes the charges (as in a lightning bolt) or the really low currents that come from the air to the ground to keep it's potential the same. There isn't really a good way of determining the earths total charge as you would have to account for all of the factors. Just call it 0V for now.

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As a planet overall, the Earth is electrically neutral.

However, the surface of the ground can have a localized charge in certain areas, such as under storm clouds.

cloud charge distribution

(Source)

The action of wind and droplets of water within the cloud causes the charge at the top of the cloud to be positive with respect to the bottom of the cloud. The strong negative charge at the bottom of the cloud also induces a corresponding positive charge in the ground directly below it.

It is this lower charge distribution that is responsible for cloud-to-ground lightning.

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  • \$\begingroup\$ But there the charge from a ground wire of electrical appliance go to when it directed to ground ? \$\endgroup\$ – calculusnoob Sep 5 '18 at 21:32
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    \$\begingroup\$ It goes wherever the electrical distribution system has its nearest connection to ground, usually at the house service entrance or at the transformer. \$\endgroup\$ – Dave Tweed Sep 5 '18 at 21:35
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Richard Feynmann explained lightning as the charges arriving from cosmic rays, collected in high-altitude clouds, and then building up potentials high enough to cause lightning bolts down to earth.

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