Particle accelerators and detectorsEdexcel International A Level Physics: Mind map

Exam questions on Particle accelerators and detectors

1. An electron gun in an evacuated tube has a heated tungsten filament. Electrons released from the filament are accelerated through a potential difference of 1500 V between the filament and a metal anode.
   Explain why the electron gun must be evacuated.2 marks
2. A cyclotron accelerates protons using two hollow D-shaped metal electrodes (dees) separated by a small gap. A uniform magnetic field of flux density 1.2 T acts perpendicular to the plane of the dees, and an alternating potential difference is applied across the gap.
   Explain why the radius of the path increases as the protons gain speed, but the time taken for each semicircle stays the same.2 marks
3. A proton moves in a uniform magnetic field of flux density 1.5 T that is perpendicular to its velocity, in a bubble chamber. It leaves a circular track of radius 0.085 m. The proton charge is 1.60 × 10⁻¹⁹ C.
   Calculate the momentum of the proton.3 marks