The KE of an electron accelerated by an electric field

[claudius]

Hello,

An electron accelerated through a pd of V volts will have a K.E = eV. Why isn't the K.E less than this considering that some of the work done by the field has been radiated as electromagnetic waves by the accelerating electron ?

All insights very welcome.

 

[tech99]

Hello,

An electron accelerated through a pd of V volts will have a K.E = eV. Why isn't the K.E less than this considering that some of the work done by the field has been radiated as electromagnetic waves by the accelerating electron ?

All insights very welcome.

The generator will do work in accelerating the electron, because a current is flowing, and must supply energy not only to KE but also to radiation and building a magnetic field. This means the electron takes longer for its journey than for KE only. Power is V x I but total energy is V x I x Time.