Question

Define electron volt and express it in joule. 

Answer 1

Electron volt : “The electric work done when an electron moves through an electric field at a potential difference of 1 volt.” 

1 electron volt (eV) = charge on 1 electron x 1 volt 

= 1.6 x 10^-19C x IV 

= 1.6 x 10^-19J [∵ 1C x IV = 1J) 

1[eV] = 1.6 x 10¹⁹J.