In a mass-spectrometer velocity selector

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism

Problem

In a mass-spectrometer velocity selector, the magnetic field is fixed at

0.20\,\text{T}

. When the electric field between the plates is adjusted to

3.0\times10^{4}\,\text{V/m}

, only particles of species A pass straight through. When the electric field is increased to

4.5\times10^{4}\,\text{V/m}

, only particles of species B pass straight through. What is the ratio of the speed of species A particles to that of species B particles? (a)

\dfrac{3}{4}

(b)

\dfrac{3}{2}

(c)

\dfrac{2}{3}

(d)

\dfrac{4}{5}