Calculate mass of oil droplet between parallel plates

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SUMMARY

The discussion centers on calculating the mass of an oil droplet held between parallel plates with a potential difference of 39.8 kV and separated by 1.89 cm. The key equations involved are E=0.5QV and C=Q/V, which relate to electric energy and capacitance. The solution requires equating the electric force acting on the droplet to its gravitational force, assuming the droplet is stationary. This approach simplifies the problem, allowing for a straightforward calculation of the droplet's mass.

PREREQUISITES
  • Understanding of electric force and gravitational force concepts
  • Familiarity with the equations for electric energy (E=0.5QV) and capacitance (C=Q/V)
  • Knowledge of basic physics principles related to charged particles
  • Ability to perform unit conversions, particularly for voltage and distance
NEXT STEPS
  • Calculate the electric force on a charged particle in an electric field
  • Explore the relationship between charge, voltage, and energy in electrostatics
  • Investigate the concept of capacitance and its applications in circuits
  • Learn about the effects of gravity on charged particles in different environments
USEFUL FOR

Students studying physics, particularly those focusing on electromagnetism and mechanics, as well as educators seeking to explain the principles of forces acting on charged objects.

PhysicsMan999
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Homework Statement



  1. A droplet of oil, carrying an extra charge of one electron, is held motionless between parallel plates separated by 1.89 cm, with a potential difference of 39.8 kV. What is the mass of the droplet?

2. Homework Equations

E=0.5QV
C=Q/V

The Attempt at a Solution


Really don't even know how to start here..I figured I would need kinetic energy to find the mass but the velocity is 0, so there would be none.[/B]
 
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PhysicsMan999 said:

Homework Statement



  1. A droplet of oil, carrying an extra charge of one electron, is held motionless between parallel plates separated by 1.89 cm, with a potential difference of 39.8 kV. What is the mass of the droplet?

2. Homework Equations

E=0.5QV
C=Q/V

The Attempt at a Solution


Really don't even know how to start here..I figured I would need kinetic energy to find the mass but the velocity is 0, so there would be none.[/B]

The problem should really tell you this, but you should assume that the force holding the droplet fixed is the weight of the droplet. Find the electric force on the droplet and set it equal to the gravitational force.
 
Oh, well that was easy then. Thanks!
 

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