1. The problem statement, all variables and given/known data I have to find out a relationship between the deflection of an electron beam in a cathode ray tube and the accelerating voltage. 2. Relevant equations I know that theoretically D is inversely proportional to the accelerating voltage. 3. The attempt at a solution I have to do this experimentally and they are giving me data tables. To find out the deflection (D) they give me: Accelerating Voltage: 400 V First Position: 5.00 cm Second Position: 9.00 cm To find out the deflection (D), they tell me to subtract the two positions and divide by 2. I don't understand what first position and second position refer to. Why do I need to divide by 2? I actually don't know how a cathode ray tube works and why would it provide 2 different positions for the same accelerating voltage. I don't know if I provided enough details, but any suggestions or ideas are greatly appreciated.