IntroductionThe historic results of this experiment by determining the charge/mass ratio of an electron allowed the physicist to calculate the tiny mass of an electron through the use of an external magnetic field. Magnetic fields apply a magnetic force on charged particles perpendicular to their direction of motion and to the magnetic field itself. This allows the magnetic force to act as a centripetal force which then, through analysis, allows the determination of certain charged particles through analysis of their radius of curvature. In Lab 15, Measuring the Charge-to-Mass Ratio for Electrons, the objective was to measure the charge-to-mass (e/m) ratio of an electron through the use of a mercury vapor chamber. This was done through graphical analysis using the linearized equation (4). The goal was to construct a line graph in which the slope and slope error were calculated using the Linest function, the slope that allows the charge/mass ratio of an electron to be derived. Error propagation (error formulas) was also used in this experiment to account for sources of errors that may have occurred. Equations used: Kinetic energy: 1/2 mv2=eV, where m is the mass of an electron, v is the velocity of the electron, e is the elementary charge of an electron, and V was the voltage used in the experimental calculation. Lorentz force: eVB=m(v2/r) =eV(Bh-Be), this explains the centripetal force making it equal to the magnetic force acting on the mercury beam (electrons). Same variables as equation (1) except that r is the radius of curvature of the mercury beam, Bh is the magnetic field of the Helmholtz coil, and Be is the magnetic field of the Earth. This equation together with the kinetic energy equation leads to the derivation of...... middle of paper ...... amber to visualize the photons released from de-energized mercury atoms and the physical phenomenon of how the particles charges are affected in a magnetic field in this laboratory allowed the manipulation of current and voltage to produce a value of the charge-to-mass ratio of an electron. The experimental value was determined to be 3.97x1010 C/Kg, while the theoretical value is 1.76x1011 C/Kg. Therefore, this experiment showed accurate results with fewer sources of error, determined to be: the effect of the Earth's magnetic field and imprecise measurements. Ultimately, the physical principles of magnetism, current, and voltage were used during this experiment. In conclusion, the calculation of the charge/mass ratio of an electron is possible through the use of graphical analysis corresponding to the equation (r) and error propagation, creating a successful experimental measurement.