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gudeapp
gudeapp
Student
College - Freshman

Langmuir's formula approximates v. well the electric current in a vacuum diode.Find how much is increasing the electronic bombardments force to anode

The anodic voltage is incresing n times.

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Posted by gudeapp on Monday June 29, 2009 at 3:00 AM and tagged with anodic voltage, electric current, science, vacuum diode.

Answers:

  1. giorgiana1976
    giorgiana1976 Teacher
    Doctorate

    eNotes Editor

    Best answer as selected by question asker.

    The force is calculated with the help of the second principle of the mechanics, variation of propulsion in unity of time:

    F=delta p/delta t.

    We consider that electrons enter in anode without displacing others and each electron will transmit it's impulse to anode, because the electron will move in anode with drift speed.

    So,variation of propulsion in unity of time of anode is the impulse "m*v" , brought by the electron multiplied with the numbers of electrons which hit the anode in  unity of time.

    F=(l/e)*m*v=l*sqrt(2U/(e/m)=K*U^(3/2)*sqrt(2U/(e/m)=

    =K*sqrt(2m/e)*U^2

    So if the voltage increases n times, the force will increase n^2 times.

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    Posted by giorgiana1976 on Monday June 29, 2009 at 12:35 PM