Electrons in a television set

In summary, the problem involves using a pair of horizontal plates in a television set to deflect electrons towards the top of the screen. The plates have a length and separation of 0.04 m and 0.012 m respectively, with a potential difference of 200 V applied across them. The electrons enter horizontally at a velocity of 6.0*10^7 m/s and fringing effects and gravity are negligible. The three questions to be determined are: 1) which plate must be at a higher potential for upward deflection, 2) the time required for the electron to move through the plates, and 3) the vertical displacement of the electron while between the plates. To solve these questions, one must calculate the
  • #1
krosenberg
6
0
A pair of horizontal plates is used to deflect electrons up or down in a television set by placing a potential difference across them. The plates have length 0.04 m. and separation 0.012 m, and the right edge of the plates is 0.50 m from the screen. A potential difference of 200 V is applied across the plates, and the electrons are deflected toward the top of the screen. Assume that the electrons enter horizontally midway between the plates with a separation of 6.0*10^7 m/s and that fringing effects at the edge of the plates and gravity are negligible.

Determine:
1) which of the two plates must be at the higher potential for the electrons to be deflected upward
2) the time required for the electron to move through the plates
3) the vertical displacement of the electron while it is between the plates
Photo373.jpg



I'm totally lost in this problem, but have a feeling we need to find the acceleration of the electron.
 
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  • #2
Well 1) is simple enough, and you should know offhand that higher potential means more/less charge(you pick the right one!) and opposite for lower potential. In that case, will the electron be attracted towards the side with more or less charge?

2)Don't think "omg a cathode ray tube question wtf"

You've got something traveling right with a known velocity which experiences a force. You can calculate this force because you know all the charges and potentials involved and yes, (edit)you can also calculate the acceleration. At that point it's a basic physics 1 problem, use your basic equations and all that

3)If you can do 2 you can do 3
 
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  • #3


I can provide a response to this content by breaking down the given information and using relevant equations from electromagnetism to solve for the requested quantities.

1) To determine which of the two plates must be at a higher potential for the electrons to be deflected upward, we can use the equation for the electric force on a charged particle: F = qE, where F is the force, q is the charge of the particle, and E is the electric field. In this case, the electric field is created by the potential difference applied across the plates, and the force acts in the direction of the electric field. Since the electrons are negatively charged, they will experience a force in the direction opposite to the electric field.

Therefore, in order for the electrons to be deflected upward, the electric field must point downward, which means that the top plate must be at a higher potential than the bottom plate. This makes intuitive sense, as the electrons will be attracted to the positively charged top plate and repelled by the negatively charged bottom plate.

2) To determine the time required for the electron to move through the plates, we can use the equation for the acceleration of a charged particle in an electric field: a = qE/m, where a is the acceleration, q is the charge of the particle, E is the electric field, and m is the mass of the particle. In this case, we can assume that the electric field is constant between the plates, and therefore the acceleration of the electron will also be constant.

We can rearrange the equation to solve for time: t = √(2d/a), where d is the distance between the plates. Plugging in the given values, we get t = √(2*0.012 m / (1.6*10^-19 C * 200 V / 0.04 kg)) = 1.2*10^-6 seconds. This means that it takes the electron 1.2 microseconds to move through the plates.

3) Finally, to determine the vertical displacement of the electron while it is between the plates, we can use the equation for the displacement of a particle under constant acceleration: d = 1/2 * a * t^2. Plugging in the values we have calculated, we get d = 1/2 * (1.6*10^-19 C * 200 V / 0.04 kg) * (1.2*
 

1. What are electrons in a television set?

Electrons are tiny, negatively charged particles that are constantly moving in a television set. They play a crucial role in the functioning of the television.

2. How do electrons create an image on a television screen?

Electrons are emitted from a cathode and accelerated towards a screen by an anode. As they move through the television's circuitry, they are controlled by electromagnetic fields and directed towards specific areas of the screen, creating an image through a process called phosphor luminescence.

3. What is the role of electrons in color television?

In color television, three separate electron beams are used to produce red, green, and blue light. These beams are directed towards the screen, where they mix and produce a full range of colors to create a color image.

4. How are electrons controlled in a television set?

Electrons in a television set are controlled by varying the strength of electromagnetic fields. These fields are created by different components, such as coils and capacitors, and are responsible for directing the electrons towards different areas of the screen to create the desired image.

5. Can electrons in a television set be harmful to humans?

No, electrons in a television set are not harmful to humans. They are present in very small quantities and are safely contained within the television's circuitry. However, it is important to use caution when handling the television's internal components, as they may carry a high voltage charge.

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