The electron beam inside a television picture tube is 0.4 mm in diameter and carries a current of 55 µA. This electron beam impinges on the inside of the picture tube screen.
A) The electrons move with a velocity of 3.9 multiplied by 107 m/s. What electric field strength is needed to accelerate electrons from rest to this velocity in a distance of 5.0 mm?
B) Each electron transfers its kinetic energy to the picture tube screen upon impact. What is the power delivered to the screen by the electron beam?