Deflection distance for an electron beam in an electric field

In summary, the conversation is discussing a question where the answer should be 17.6 cm, but there is confusion on whether the electric field direction should be downward or upward. The person who wrote the question may have made a mistake with the decimal point, resulting in an incorrect answer of 1.76 cm. It is also mentioned that this type of mistake happens frequently when old problem sets are updated.
  • #1
Bolter
262
31
Homework Statement
See question below
Relevant Equations
F = qE
Have tried doing this question but I'm a bit confused on where I'm going wrong

Screenshot 2020-03-07 at 22.32.02.png

This is what I have done but get a value that doesn't match to any of the options given above?

IMG_4055.JPG


Any help would be really appreciated, Thanks!
 
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  • #2
I agree with your answer of 17.6 cm. Your work looks very good. But in your diagram, if the electric field is downward, would the electron be deflected downward?
 
  • #3
TSny said:
I agree with your answer of 17.6 cm. Your work looks very good. But in your diagram, if the electric field is downward, would the electron be deflected downward?

Sorry my field line directions should be reversed (going from positive to negative)

So the question must have a mistake then I guess. I believe the first option would’ve been the right answer but maybe the person who wrote this misplaced the decimal point position and instead got 1.76cm and not 17.6cm :oldconfused:
 
  • #4
Bolter said:
Sorry my field line directions should be reversed (going from positive to negative)

So the question must have a mistake then I guess. I believe the first option would’ve been the right answer but maybe the person who wrote this misplaced the decimal point position and instead got 1.76cm and not 17.6cm :oldconfused:
Yup. Given the question-given values the beam will impact the positive plate about halfway through the parallel plate channel. So original problem statement FAIL. This happens frustratingly frequently, especially when older problem sets are "updated" to change the working values to "refresh" the problem for new editions of texts or exams.
 
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Likes Bolter and TSny

FAQ: Deflection distance for an electron beam in an electric field

1. What is the deflection distance for an electron beam in an electric field?

The deflection distance for an electron beam in an electric field refers to the distance that an electron beam will be deflected when passing through an electric field. It is determined by the strength of the electric field and the charge and mass of the electron.

2. How is the deflection distance calculated?

The deflection distance can be calculated using the equation d = (E * L^2) / (2 * m * V^2), where d is the deflection distance, E is the electric field strength, L is the length of the electric field, m is the mass of the electron, and V is the velocity of the electron beam.

3. What factors affect the deflection distance of an electron beam?

The deflection distance of an electron beam is affected by the strength of the electric field, the length of the electric field, the mass and charge of the electron, and the velocity of the electron beam. Additionally, the shape and orientation of the electric field can also impact the deflection distance.

4. How does the deflection distance change with increasing electric field strength?

The deflection distance increases with increasing electric field strength. This is because a stronger electric field will exert a greater force on the electron beam, causing it to deflect more.

5. Can the deflection distance be controlled?

Yes, the deflection distance of an electron beam in an electric field can be controlled by adjusting the strength and shape of the electric field, as well as the velocity of the electron beam. This allows for precise manipulation and positioning of the electron beam in various scientific and technological applications.

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