Activity : To measure e/m of Electron by Thomson Method Bar Magnet method. One method of demonstration modern physics in the controlled bending of stream of high speed electrons in a magnetic field. The actual measurement by students of the ratio of the charge on the electron to its equally minute mass imparts a stimulating sense of achievement. e/m apparatus has been perfected to the point where it is possible for this fundamentally important measurement to be carried out with good accuracy. Power Supply : E.H.T. 800V D.C. for cathode Voltage to C.R. tube. 0-100 volts D.C. with moving coil meters to measure the Deflecting voltage either y1 or y2 Plates. Cathode Ray tube fitted on wooden frame with scale divided in centimeters. Deflecting Magnetometer with permanent magnetic compass included. Compass stand, a pair of Bar Magnet.