Day 2 Charged Particles Moving Through Magnetic Fields Magnetism Day 2 Charged Particles Moving Through Magnetic Fields

When will it? When won’t it? When a charged particle travels through a magnetic field, it “might” experience a force. When will it? When won’t it? When a component of the magnetic field is perpendicular to the particle’s velocity. When the velocity of the particle and the velocity are either PARALLEL or ANTI-PARALLEL.

Right Hand Rule #1 (or RHR-1): Finding the direction of the force exerted on a positive charge moving through a magnetic field  

Some Examples

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OK, so RHR-1 gives us the direction of the force OK, so RHR-1 gives us the direction of the force. But since force is a vector, can we find the MAGNITUDE of the force? Magnetic Field Strength (measured in Teslas, T) Velocity of the particle (m/s) Charge of the particle (C) NOTE: This equation is only valid if B and v are perpendicular to each other!!!

What exactly is a Tesla? 1 T = _____________ 1T is REALLY big. So we often us prefixes like mT, mT, or nT. The earth’s magnetic field is soooooo small that we often use a term called a GAUSS (G) to measure it. 1 G = 0.1mT (and the earth’s magnetic field is ~ .1-.3 G)

But what if v and B are NOT perpendicular? Magnetic Field Strength (measured in Teslas, T) Velocity of the particle (m/s) Charge of the particle (C) The angle between v and B

What if q = 0? F = ____ What if q = 90? What if q = 180? qvB

What would you have to do to make the path helical? What would happen if …… + - What would you have to do to make the path helical?

Use the radius of the motion to find the mass. Mass Spectrometer Only ions with a certain speed make it through….thus, if an ion makes it through, it must have the same speed as all the other ions that make it through. Use the radius of the motion to find the mass.