Question

A velocity (2.67 × 10⁶ m/s) selector in a mass spectrometer uses a 0.246-T magnetic field. What is the voltage between the plates if they are separated by 3.8 cm?

Answer 1

Electric field:

$E=vB$

Voltage of electric field E over distance $l$ :

$U=El=vBl=2.67\cdot10^6\cdot0.246\cdot3.8\cdot10^{-2}=2.5\ V$