A velocity selector consists of a region with perpendicular electric and magnetic fields. A beam containing a mixture of different charged particles is directed into the selector. Which statement is correct for the particles that can pass through undeflected?
The selected speed depends on both the charge and mass of the particles.
The electric field and the magnetic field must be in the same direction.
Both positively and negatively charged particles with the same speed can pass through undeflected.
Only particles with a positive charge are able to pass through undeflected.
34 exam-style questions on OCR A A Level Physics Electromagnetism, covering Magnetic fields, Motion of charged particles, and Electromagnetism. Each one has a worked solution and a mark scheme showing where the marks go.