Question

As shown in the diagram, an electron enters perpendicularly into a magnetic field. Using Fleming’s Left-Hand Rule, determine the direction of the force experienced by the electron. 

Hint:

For electrons, reverse the current direction while applying Fleming’s Left-Hand Rule.

Answer 1

Given:
Electron is moving upward.
Magnetic field is into the page (leftward in diagram).
Electron is negatively charged, so the direction of current is opposite to the motion of the electron, i.e., downward.
Now, applying Fleming’s Left-Hand Rule:
First finger → magnetic field (left)
Middle finger → current (downward)
Thumb → force on the conductor → out of the plane of the paper (towards observer)
Thus, the electron experiences a force in the inward direction (into the page) because the actual force direction is opposite for negatively charged particles.