1 volt = `overset(?)-` esu of potential?

Define 1 esu of potential.

1 watt - overset(?)___ .

1 kilowatt = overset(?)_ watt

1 stat volt = ? Volt?

1 kilowatt-hour = overset(?)_ Joule?

1 horsepower = overset(?)_ watt

1 unit = overset(?)_ kilowatt-hour?

1 kilo ampere = overset(?)_ Ampere?

What is the relaton between volt and esU potential?

A metal sphere of radius 10 cm is charged up to a potential of 80 esu. After sharing its chage with another sphere, the common potential of them becomes 20 esu. What is the radius of the second sphere ?