Purpose
1.To study the effect of electric and magnetic fields on charged particles and to
measure the charge to mass ratio of an electron.(1/2) m v2 = e V (3)
Combining equations (2) and (3) gives
e / m = ( 2 V / B2 r2) (4)
Thus, when the accelerating voltage V, the magnetic field B, and the radius of the
circular path r are known, the value of the e/m ratio can be computed and is given in
units of C/kg by equation (4) if V is in volts, B in Teslas and r in meters.Theory
When an electron moves in a magnetic field B whose direction is perpendicular to
the velocity v of the particle, it is acted on by a force F perpendicular to B and v with
a magnitude given by:
|The force F is equal to the
mass of the particle times the centripetal acceleration
e v B = m v2 / r (2)
where r is the radius of the circle and m is the mass of the electron.More practice in error analysis.2.F |