What happens when a charged particle moves in a magnetic field?

The charged particle experiences a force which is perpendicular to both the direction of motion and the magnetic field.

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What is the direction of the force on a charged particle moving in a magnetic field?

The force is always perpendicular to the direction of motion and the direction of the magnetic field.

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What is the formula linking force (F), magnetic flux density (B), charge (Q) and velocity (v)?

F = BQv


F = force (N)

B = magnetic flux density (T)

Q = charge (C)

v = velocity (m s-1)

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What is the shape of the path of a charged particle moving in a magnetic field?

The path is a circle.


This is because the force on the charged particle is always perpendicular to its motion.

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What is a velocity selector?

A velocity selector is a device that selects particles with a specific velocity, using both an electric and a magnetic field.

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In a velocity selector, what happens to particles moving too fast?

Particles moving too fast are deflected in the direction opposite to the electric field.

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In a velocity selector, what happens to particles moving too slow?

Particles moving too slow are deflected in the direction of the electric field.

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What is the formula linking velocity (v), electric field strength (E), and magnetic flux density (B) for a velocity selector?

 

v = BE​


v = velocity (m s-1)

E = electric field strength (V m-1)

B = magnetic flux density (T)

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What is the force on a charged particle that moves parallel to a magnetic field?

Zero

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What is the force on a stationary charged particle in a magnetic field?

Zero

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What happens to the radius of the circular path of a charged particle in a magnetic field when its velocity increases?

The radius of the circular path increases.

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What happens to the radius of the circular path of a charged particle in a magnetic field when its charge increases?

The radius of the circular path decreases because the force on the charged particle increases.

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