Protons produced in a particle accelerator exit a drift tube with speed 1.2×10⁶ m s⁻¹…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Protons produced in a particle accelerator exit a drift tube with speed 1.2×10⁶ m s⁻¹ and immediately enter a 10 cm long region containing a uniform electric field of magnitude 7.0×10³ N C⁻¹ directed downward. To keep the protons moving in a straight horizontal line, a scientist adds a uniform magnetic field perpendicular to both the proton velocity and the electric field.
(1) Determine the magnitude and direction of the magnetic field required for the protons to remain undeflected.
(2) Calculate the work done by the electric force on a proton while it traverses the 10 cm region if the magnetic field is set as in part (a). Explain why this result is physically reasonable.
(3) The scientist would like to adapt the apparatus for deuterons (charge +e, mass 3.4×10⁻²⁷ kg) that have the same entry speed. Determine whether the magnetic field must be adjusted to keep the deuterons undeflected, and justify your answer quantitatively.