A charge 10 esu is placed at a distance of 2 cm from a charge 40 esu and 4 cm from another charge -20 esu. The potential energy of the charge 10 esu is : (in ergs)

A negative charge of 30 esu is at a distance of 30 cm from a positive charge of 20 esu. What is the potential at a point 10 cm from the first charge on the line joining the two charges? Where will the potential be zero?

A point charge of +10 mu C is placed at a distance of 20 cm from another identical point charge of +10 muC . A point charge of -2mu C is moved from point a to b as shown in the figure . Calculate the change in potential energy of the system ? Interpret your result .

Define 1 esu of charge

Number of esu of charge in 1C is

The ratio of the emu of charge to esu of charge is :

The unit of charge in esu is_____ and emu is_____.

A small pith ball of mass 0.3 g is suspended by a weightless thread between two vertical parallel plates, separated by a distance of 5 cm. The ball carries a charge of 49 esu. What potential difference should be applied between the plates so that the thread is deflected by 45^(@) from the vertical?