Abstract: In this experiment we measured the deflection of a light beam traveling through a CRT tube when different amounts of voltage were supplied to the tube. We found that when the voltage supplied to this device was increased the deflection of the light beam decreased. We also found that the product of the slope of the line from each set of points and the supplied voltage was equal to a constant, implying that the slope is inversely proportional to the amount of power supplied.
The device used in this experiment was a Cathode Ray Tube (CRT). "This is a vacuum tube in which a beam of electrons is accelerated and deflected under the influence of electric or magnetic fields." "The electrons are deflected in various directions by two sets of plates placed at right angles to each other in the neck of the tube."  "An external electric circuit is used to control the amount of charge present on the plates. The placing of positive charge on one horizontal plate and negative charge on the other creates an uniform electric field between the plates and allows the beam to be steered from side to side."  This tube is used to measure the deflection of the beam, which than means that the more the beam deflects when measured, the more intense the electric field is between the two plates.
You can see this relationship in the equation: .
Where E is the electric field, V is the voltage, and d is the distance between the plates.
The motion of the electrons threw the CRT can be described by a number or equations, but the one used for this experiment directly was:.
Where A is the acceleration, E is the charge of uniform electric field, q is the charge of the particle, and m is the mass of the particle. As you can see from the equation the acceleration is inversely proportional to the strength of the uniform electric field created. The stronger the electric field the less acceleration the electron has.