The electron beam inside a television picture tube is 0.40 mm in diameter and carries a current of 50 A. This electron beam impinges on the inside of the picture tube screen.
How many electrons strike the screen each second?
The electrons move with a velocity of 4.0 X 10^7 m/s. What electric field strength is needed to accelerate electrons from rest to this velocity in a distance of 5.0mm?
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? (Hint: What potential difference produced the field that accelerated electrons? This is an emf.)