A sample of two different irons, Fe2+ and Fe3+, are accelerated by the same potential and then sent through the uniform magnetic field of a mass spectrometer.
a) Which ion moves faster after being accelerated?
b) Which ion follows the path with the largest radius?
a) Which ion moves faster after being accelerated?
b) Which ion follows the path with the largest radius?
-
(a) = +3 ion
(b) = +2 ion
Both ions have (virtually) the same mass, the +3 ion has a greater accelerating force so acquires a greater velocity.
from eV = ½mu²
u2 = √(4eV/m)
u3 = √(6eV/m) ◄ larger velocity
In the magnetic field R = mu/Bq .. (from Bqu = mu²/R)
R2 = k.(√4)/2 = k 1.0 ◄ larger radius [k = m√(eV/m)/Be]
R3 = k (√6)/3 = k 0.8
(b) = +2 ion
Both ions have (virtually) the same mass, the +3 ion has a greater accelerating force so acquires a greater velocity.
from eV = ½mu²
u2 = √(4eV/m)
u3 = √(6eV/m) ◄ larger velocity
In the magnetic field R = mu/Bq .. (from Bqu = mu²/R)
R2 = k.(√4)/2 = k 1.0 ◄ larger radius [k = m√(eV/m)/Be]
R3 = k (√6)/3 = k 0.8