Case study·Hard exam skill (4/5)·Calculator allowed
Difficulty guide
The label describes the problem, not your ability.
1/5 - Foundational
Warm-up setup; checks one basic idea.
2/5 - Routine exam skill
Normal syllabus skill; usually one main rule or interpretation.
3/5 - Standard multi-step
Exam-style problem with multiple steps or a common trap.
4/5 - Hard exam skill
High-end exam problem; combines methods carefully.
5/5 - Challenge
Stretch problem beyond normal exam pressure.
Question
In a mass-filter experiment, positive ions enter a region with velocity to the right. The electric field is downward and the magnetic field is into the page, as shown. The fields have magnitudes and .
Total: 5 marks
(a) Find the speed for which the ion passes undeflected. (2 marks)
(b) For a faster positive ion, compare the magnetic and electric force magnitudes. (1 mark)
(c) For a faster positive ion, state the direction of deflection. (2 marks)
Something wrong with this item?