We just began looking at uniform electric fields at school and for the weekend we were given some problems to complete. I came to one of the problems which involved a concept i am unsure about and so have had trouble completing the problem. I am a unsure of what it means when something has been earthed, so would somebody be able to help me with the following problem, and also if possible, expalin to me what it means when somethng has been earthed:

 

What would the potential difference be between two parallel plates if the upper plate is at a potential of 1000V and the lower plate is earthed?

Do you mean grounded?

 

If so what is somethings potential difference when it is grounded?

yes earthed means grounded. it means the voltage on it is 0V

It literally means attached to the Earth. The Earth has a voltage of zero.

 

An example of earthing is when you see a wire/cable running down the side of a tall building. One end of the cable is at the top of the building, the other in ground. The idea of those is that lightning is attracted to it and goes through it straight (and safely) into the ground, as opposed to potentially damaging the building.