PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Two singly-charged particles, one a positive ion and the other an electron, each enter a region of uniform magnetic field at the same point and at the same instant. The magnetic field is directed due north with magnitude 0.40T. Immediately before entering the field, both particles are moving horizontally toward the east with identical speeds.
Answer the following questions. You may add clear, labeled sketches to support your explanations.
(a) Describe the direction of the magnetic force acting on each particle at the instant they enter the field. Explain the reasoning that leads to each direction.
(b) Compare the magnitudes of the magnetic forces on the two particles. Justify your answer without performing a numerical calculation.
(c) Describe qualitatively the subsequent paths followed by the ion and the electron while they remain in the magnetic field. Include a comparison of radii of curvature and directions of motion.
(d) Suppose instead that the particles entered the field with identical speeds but along directions 30∘ north of east. Predict how the initial magnetic forces and resulting motions would change, and explain your reasoning.