Vertical Displacement of Electron (Millikan's Oil Drop)

In summary, the conversation discusses the problem of determining the vertical displacement of an electron as it travels between two parallel plates under the influence of an electric field. The solution involves finding the electric force, acceleration, and time, and then using kinematics to determine the vertical displacement. The initial vertical speed of the electron is also mentioned as a key factor in solving the problem.
  • #1
honeybee63
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0

Homework Statement



An electron moving horizontally at 2.50 x 106 m/s enters a 150 N/C electric field exactly half way between two horizontal parallel plates and follows a parabolic path downwards. Both plates are 14 cm long and spaced 10 cm apart. Determine the vertical displacement of the e- as it travels between the plates.

Homework Equations



E = Fe/q , F=ma , Ep = mgh

The Attempt at a Solution



I found Fe by E/q and got 2.40 x 10-17 J. then I plugged the values into F=ma and found the acceleration to be 2.63 x 1013 m/s2. I then divided the velocity by acceleration and found time to be 9.49 x 10 -18 s. I am now unsure how to find the vertical distance. I used Ep = mgh but got a very large value, so I think that is wrong. Did I make a mistake earlier or should I be using a different equation?
 
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  • #2
honeybee63 said:
I then divided the velocity by acceleration and found time to be 9.49 x 10 -18 s.
The velocity is horizontal but the acceleration is vertical. Instead, ask how long does it take something moving that fast to cover the needed distance?

Once you have the time, figure out its vertical displacement in that time using kinematics. What is the electron's initial vertical speed?
 

FAQ: Vertical Displacement of Electron (Millikan's Oil Drop)

1. What is the significance of Millikan's Oil Drop experiment?

Millikan's Oil Drop experiment is significant because it provided the first direct measurement of the charge of an electron. This experiment also helped to confirm the existence of discrete electric charges, which was a major breakthrough in understanding the behavior of subatomic particles.

2. How does the vertical displacement of electrons in Millikan's Oil Drop experiment work?

The vertical displacement of electrons in Millikan's Oil Drop experiment is caused by the opposing forces of gravity and electrical attraction between the charged oil droplet and the charged plates. By applying an electric field, the droplet can be suspended in mid-air, allowing for precise measurements of its charge and mass.

3. What are the key factors that affect the vertical displacement of electrons in Millikan's Oil Drop experiment?

The key factors that affect the vertical displacement of electrons in Millikan's Oil Drop experiment are the strength of the electric field, the mass and charge of the oil droplet, and the density of the surrounding air. These factors must be carefully controlled and measured to obtain accurate results.

4. How did Millikan determine the charge of an electron using his experiment?

Millikan determined the charge of an electron by measuring the vertical displacement of oil droplets in his experiment and using the known values of gravity and the electric field strength. By adjusting the electric field and measuring the displacement of multiple droplets, he was able to determine the charge of each droplet and found that they were all multiples of a single, fundamental charge - the charge of an electron.

5. What are some practical applications of Millikan's Oil Drop experiment?

Millikan's Oil Drop experiment has had significant impacts in various fields such as physics, chemistry, and engineering. It has helped to improve our understanding of the behavior of subatomic particles and has been used in the development of technologies such as particle accelerators, mass spectrometers, and inkjet printers. It has also been used to study the properties of other charged particles, such as protons and ions, and to determine their charges and masses.

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