Physics--Electrons and Kinetic Energy?

Question

An electron passes a point where the potential is 5V, with a kinetic energy of 7eV. Some time later it passes a point where the potential is 8V. What is its kinetic energy there, in eV and in J?

Thanks!!

Answer 1

♠ Its total energy is

E=E1+E2, where E1=7eV,

E2=e*(8V –5V) = 3eV;

Therefore E=7+3 =10eV; and

♣charge of electron is e= 1.602e-19 C;  

thus E= 1.602e-19 *10 = 1.602e-18 J;