In the presence of an external magnetic field (not shown), a proton initially traveling upward is deflected into the path labeled as A in the following figure. What would be the expected path for an electron in the same magnetic field?

Question

In the presence of an external magnetic field (not shown), a proton initially traveling upward is deflected into the path labeled as A in the following figure.  What would be the expected path for an electron in the same magnetic field?

Quizplus · Accepted Answer

11ecba2d_1304_0de6_a3bf_957acbcf79e7_MD0008_00 Moving charged particles are accelerated in a magnetic field by the Lorentz force. The direction of the force is always perpendicular to the particle's velocity. As a result, the particle's trajectory is forced into a curved path. In the figure, the path of the proton is bent to the left in the presence of the external magnetic field. This means that the Lorentz force initially points to the left for positive charges in the magnetic field. The direction of the Lorentz force for positive charges can be determined by using the right-hand rule. The direction of the force is in the opposite direction for negative charges. Therefore, the trajectory of an electron would curve in the opposite direction toward the right (Choices A and C). Because the mass and inertia of an electron is much lower than that of a proton, the electron will be more greatly affected by the magnetic field, and its path will curve more. (Choice B) A particle with a negative charge and the mass of a proton would follow this path. Educational objective: The Lorentz force exerted on a moving charge in the presence of a magnetic field is perpendicular to the particle's velocity. As a result, the charge's trajectory is forced into a curved path, with negative charges and positive charges bent in opposite directions. Because an electron is less massive than a proton, an electron's path would be more curved in the same magnetic field.

In the Presence of an External Magnetic Field (Not Shown)