velocity selector

A velocity selector is a device used in physics to filter molecules or particles, allowing only those within a narrow range of speeds to pass through. This is typically achieved using rapidly spinning slotted disks or cylinders. Particles with the correct speed will travel through a slot without hitting its sides, while particles moving too fast or too slow will be obstructed. Changing the rotation speed of the selector alters the range of velocities that can pass. This is crucial for experiments where uniform particle speed is necessary for accurate study of their properties, such as in molecular beam experiments. The interaction of magnetic fields with moving charges is also relevant, as magnetic fields exert forces on moving charged particles, influencing their paths.12