I am trying ti understand this problem and how to solve it before I go to my lab

Question

I am trying ti understand this problem and how to solve it before I go to my lab

can anyone help me ?

Work this problem on a whiteboard A cathode ray tube (CRT) is used to accelerate and direct the path of electrons. They were commonly used in monitors and TVs, before LCDs became more popular. A CRT is housed within evacuated ilament (not unlike the ones that you can find in lightbulbs), causing it to heat up enough to boil off electrons. The electrons then pass through two conducting plates (labeled A and 8 in the diagram). A voltage (Vacc) is run across the plates in arder to accelerate the electrons in a straight path towards another set of plates and cols. A potential difference sVdef is run across the second set of plates (labeled Cand D in the diagram). The voltage here is adjustable and allows for deflection of the electrons At one end of the apparatus, current is run through a Two coils are positioned on opposite sides of the second pair of plates. when ourrent is run through the coils, a magnetic field is produced in the region of the two deflection plates. In this problem, the coils are oriented so as to create a magnetic field into the page (when using the diagram below). Under the right con the beam is therefore allowed to follow a straight path (red path in the diagram below), as well as paths that curve either up or down (blue path in the diagram below). ol AV. coil D° this problem on a whiteboard Because the apparatus is fragile, and requires a high voltage power supply, only your instructor will operate the apparatus. Your job is to determine the speed of the electrons in the beam in the CRT tube, using two diferent approaches, and compare your results, In order to do this you will need to ask the instructor to measure various quantities. On your whiteboard, outine a plan for this cakculation, and list the measurements you will need

Explanation / Answer

The two coils help to guide the motion of electron , this works upon the principle that any charge particle moving in a magnetic field experiences a force of magnitude |F|=|qV×B|,the coil produces and help maintain a magnetic field in the region . Having known the trajectory of electron in magnetic field ,it's initial velocity, length of column which electron would cover and the acceleration of electron(calculated by knowing accelerating potential end, as F=V/(dx.q)=ma,note:-dx is the length to which accelerating potential is applied)... By applying simple kinematical equations one can easily evaluate the velocity of electrons (1st method).

Also velocity of electrons can be calculated at coil end, the magnetic force will tend to provide a centrepetal acceleration and so mv^2/R= qvB from this equation velocity of electron can be calculated.(method2) now one can easily deduce that what all measurements of variable required .

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.