Millikan Oil Drop Question

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Millikan Oil Drop Question
American physicist Robert Millikan won the 1923
Nobel Prize in physics. conducted a series of
experiments that measured the electrical charge
carried by an electron.
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Problem

• Two large parallel metal plates are separated by
  a distance of 2.0 x 10-3 meters.
• The plates are attached to a 4.0 x 103 volt
  source.

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Calculate

• The FIELD INTENSITY between the plates ( E V/d)
• Determine the FORCE on an electron in the FIELD (
  F q E)
• Calculate the WORK necessary to move an electron
  from the positive plate to the negative plate in
  ELECTRON VOLTS and in Joules ( W q V)

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Sample Solutions Field intensity

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Two large parallel metal plates are separated by
a distance of 2.0 x 10-3 m. The plates are
attached to a 4.0 x 10 3 V

• E V / d
• (4.0 x 10 3 V) / ( 2.0 x 10-3 m)
• 2.0 x 10 6 V/m

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Force Example
Calculate the force exerted on an electron on an
electric field, whose intensity is 2.0 x 10 19
C

• F q E
• ( 1.6 x 10 19 C ) (2.0 x 10 3 N/C)
• 3.2 x 10 16 N

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Work Example
Calculate the work necessary to move an electron
from the positive plate to the negative plate in
eV and in J.

• W qV
• 1 electron x (4.0 x 10 3 V)
• 4.0 x 10 3 eV
• Since 1 eV 1.6 x 10 19 J
• W 1 electron x (4.0 x 10 3 V)
• (1.6 x 10 19 J/ev)(4.0
  x 10 3 eV)
• 6.4 x 10 16 J

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Summary

• Robert Millikan conducted a series of experiments
  that measured the electrical charge carried by an
  electron.
• Using the potential ( volts ) formulas based on
  an electron s pressure
• Solve for FIELD INTENSITY, FORCE, and WORK on the
  electron.