The potential difference across the plates will be zero. The accelerating potential difference will be av. When the electrons enter the region between the plates, they will be deflected by the magnetic field set up by the Helmholtz coils. The electrons will be deflected along a circular arc. This arc is determined by the condition that the magnetic force acting on the electrons provides the centripetal acceleration necessary for the circular motion, i. e.. evB = mv2/R). (1) where e is the charge of an electron, 1.60 x 10 C. Ris the radius of the circular path, Bis the magnetic field, and v is the speed of the electrons. The electrons originate at the cylindrical end of the tube and are accelerated through a potential difference AV acquiring a kinetic energy given by mv = AV Solving equation (2) for v, and substituting it into equation (1). we obtain (RBP = (2me) AV (3) The magnetic field is given by the relation B = B1, (4) where 3 = 0.00465 and l is the current in amperes. Substituting BI for B into Eq.(3) and rearranging the variables, we have (RIY = (2m'eß-) AV. This is the basic equation (5) Physica en 2 Despacio Detection The radius of the path can be determined by knowing a point on the path with coordinates (x, y) and using R = 1* Cos-15* + y4y2y. (6) For each accelerating potential, Eq. (6) allows us to calculate R. Now that we know R for each accelerating potential, we can graph (RIY vs. AV, and the slope of the line will equal Zm/e32 (Note: This comes from the fact that the general form of a straight line is y=mx +b. So if (RI) is plotted on the y axis and AV is plotted on the x axis, then the slope (m) will be the coefficient of x which in this case is (2m/elsa). Now we can calculate the mass of an electron Procedures: There are four different High Voltage Power Supplies. Wire your particular High Voltage Power Supply apparatus according to the diagrams at the end of this Magnetic Deflection lab. Your lab instructor must check your connections before you turn on the power supplies