Understanding Current and its Properties: A Comprehensive Guide

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SUMMARY

The discussion focuses on the properties of current as it relates to an electron beam in a television picture tube. The beam has a diameter of 0.300 mm and carries a current of 52.0 µA, resulting in a specific number of electrons striking the screen each second. The current density is calculated based on the beam's cross-sectional area, and the required electric field strength to accelerate electrons to a velocity of 4.50 x 107 m/s over a distance of 5.70 mm is determined. Additionally, the power delivered to the screen by the electron beam is discussed, emphasizing the kinetic energy transfer upon impact.

PREREQUISITES
  • Understanding of electric current and its measurement in Amperes
  • Knowledge of electron properties and behavior
  • Familiarity with the concept of current density
  • Basic principles of kinetic energy and power calculations
NEXT STEPS
  • Calculate the number of electrons in a given current using the formula: Number of electrons = Current / Charge of an electron
  • Learn about current density calculations in different cross-sectional areas
  • Study the relationship between electric field strength, acceleration, and distance
  • Explore power calculations in electrical systems, particularly in relation to kinetic energy transfer
USEFUL FOR

Students in physics, electrical engineers, and anyone interested in the principles of electric current and its applications in technology, particularly in display technologies like CRTs.

milkman9000
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1. The electron beam inside a television picture tube is 0.300 mm in diameter and carries a current of 52.0 mu A . This electron beam impinges on the inside of the picture tube screen.

a)How many electrons strike the screen each second?

b)What is the current density in the electron beam?

c)The electrons move with a velocity of 4.50*10^7 m/s . What electric field strength is needed to accelerate electrons from rest to this velocity in a distance of 5.70 mm?

d)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?

Any help will be appreciated :smile:



Homework Equations


I=V/R


The Attempt at a Solution

 
Physics news on Phys.org
what are the UNITS of current [that is, what's an Ampere] ?
what is current MADE of ?
go back to the chapter on fluid flow, look for density times velocity times Area ...
 

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