In an experiment to determine the charge to mass ratio e/m of the electron using a cylindrical diode, the following equation is derived: e/m=8V/(r^2 B^2 ), where V is the potential difference across the diode of radius r at the critical field B. The latter is supplied by passing a current I through a solenoid of diameter D and length L, and is given by B = (μ_0 nI)/(I+D^2/L^2 )^(1/2) , where n is the number of turns per unit length. The appropriate experimental quantities are determined as follows:n = 3920 m–1; D = 0.035 + 0.001 m; L = 0.120 + 0.001 m;r = (3.4 + 0.1) × 10–3 m; 1 = 1.92 + 0.02 A; V = 20 + 1 V.Value of e/m:(a) 1.6 × 1011 C/kg(b) 1.7 × 1011 C/kg(c) 1.8 × 1011 C/kg(d) 2.7 × 1011 C/kg

Kevin Nash , 11 Years ago

Grade upto college level