please do question number 3 When the deflection voltages (V_DX and V_DY) were in

Question

please do question number 3

When the deflection voltages (V_DX and V_DY) were increased the deflection of the dot on the screen increased. However, when the accelerating voltage (V_z) was increased the deflection of the dot on the screen decreased. In both cases we were increasing a voltage - why did we get different results? Explain what is going on without using equations. A schematic of a cathode ray tube is shown below. Well assume that the x-deflection plates are inactive (so that they do not affect the electron beam) and ignore them. Follow the steps below to calculate the deflection of the electron beam in the y-direction.

Explanation / Answer

kinetic energy imparted is directly proportional to the voltage applied.

higher the kinetic energy, higher the velocity achieved.

when deflection voltages are increased,velocity along y and x direction (which is along the screen) increases

so for a fixed speed along z direction (perpendicular to screen),the particle moves further distance on the screen

and hence the deflection increases.

when acceleration potential increases, velocity along z axis increases

and time to reach the screen decreases.

so deflection along the screen decreases for constant speed along x and y direction

(for same speed along x / y direction , as distance=speed*time,

as time decreases, distance travelled decreases

hhence deflection on the screen decreases.

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