- #1
Oribe Yasuna
- 43
- 1
Homework Statement
In the simple mass spectrometer shown in the figure below, positive ions are generated in the ion source. They are released, traveling at very low speed, into the region between two accelerating plates between which there is a potential difference ΔV. In the shaded region there is a uniform magnetic field B
Determine the appropriate magnitude and direction of the magnetic field B
Magnitude B = ?
direction = ?
Homework Equations
Fmag = dp/dtmag = qvB
dp/dtmag = p(v/R) = p(omega), p = ymv
omega = q_mag * b / (ym)
The Attempt at a Solution
deltaV (I don't know what to do with electrical potential)
M (mass)
q (charge)
d/2 = R (radius)
v << c, y = 1, p = mv (approximation)
Fmag = dp/dtmag
qvB = p(v/R)
qvB = p(v/(d/2))
qB = p/(d/2))
B = p/(d/2))/q
B = 2p/dq, p = mv (approx.)
B = 2Mv/dq
This is wrong, probably because I'm not given velocity. However, I don't know how to get magnetic field without velocity? I think the problem is I don't know what to do with electric potential.
Last edited by a moderator: