An electron moving in the +x direction enters a region that has a uniform magnetic field in the +y direction. When the electron enters this region, it will do the following.

Question

be deflected toward the -y direction
be deflected toward the +z direction
be deflected toward the +y direction
be deflected toward the -z direction
continue undeflected in the +x direction

Answer 1

To determine the direction of the deflection of an electron moving in the presence of a magnetic field, we can use the right-hand rule and take into account the charge of the electron.

1. Movement in the +x direction: The velocity of the electron is in the +x direction.
2. Magnetic field in the +y direction: The magnetic field (\( \mathbf{B} \)) is in the +y direction.

Since the electron is negatively charged, we will flip the direction of the right-hand rule. The right-hand rule states that if you point your right thumb in the direction of the velocity of a positive charge (in this case, we will reverse this for the negative charge) and your fingers in the direction of the magnetic field, your palm will face the direction of the force acting on a positive charge. For a negative charge, such as the electron, the force will act in the opposite direction.

Following the right-hand rule:

• Point your right thumb in the +x direction (the direction of velocity).
• Point your fingers in the +y direction (the direction of the magnetic field).

Your palm will face in the +z direction, which corresponds to the force direction on a positive charge. Since the electron is negatively charged, it will experience a force in the opposite direction, which is -z direction.

Thus, the electron will be deflected toward the -z direction.