Electron Force B-Field: Direction & Velocity

[UrbanXrisis]

B-Field is going into the page. An electron has a velocity to the left. Force is then downwards correct?

 

[Doc Al]

No. The force is given by F = qV x B. Using the right-hand rule, and noting that the electron has a negative charge, I get that the force is up the page.

 

[cookiemonster]

I forgot which hand is my right one. It's not the left one, right?

cookiemonster

 

[UrbanXrisis]

My hands are faced down...B field into the page, means fingers curled, and if the thumb is pointing to the left, the the force is acting down.

 

[jamesrc]

My hands are faced down...B field into the page, means fingers curled, and if the thumb is pointing to the left, the the force is acting down.

When you cross the velocity vector (pointing to the left) by the magnetic field vector (pointing into the page), your thumb ends up pointing down. But, as DocAl said, because we are looking at an electron, the value of the charge (q) is negative (q = -1.6*10^-19 C). The force is therefore pointing in the negative down direction or, as we say where I'm from, up.