Question

which physical quantity does the electron volt measures

Answer 1

it is the unit of energy its value is 1.602 ×[tex]10^-19

Answer 2

Electron volt or eV is the unit of energy (electrical energy).
     e V = 1.6 * 10⁻¹⁹ coulombs (charge of an electron) * 1 volt
           = work done to bring an electron from infinity to its current location
                 having a potential of 1 Volt.

Potential energy of a system of charged particles = 
        = charge on one particle * potential voltage at the location of that charge due to the presence of other charges.
         = work done to bring the charge from infinity to that location in presence of other charges