Question

a charge is moving in a magnetic field that points to the left. what direction can the charge move and experience no magnetic force? check all that apply. up down left right into the screen out of the screen

Explanation:

Step1: Recall Magnetic Force Formula

The magnetic force on a moving charge is given by the Lorentz force law: $\vec{F} = q\vec{v} \times \vec{B}$, where $q$ is the charge, $\vec{v}$ is the velocity (direction of motion) of the charge, and $\vec{B}$ is the magnetic field. The magnitude of the force is $F = |q|vB\sin\theta$, where $\theta$ is the angle between $\vec{v}$ and $\vec{B}$. For the force to be zero, $\sin\theta = 0$, which means $\theta = 0^\circ$ or $\theta = 180^\circ$. This implies the velocity (direction of motion) of the charge must be parallel or antiparallel to the magnetic field.

Step2: Analyze the Magnetic Field Direction

The magnetic field $\vec{B}$ points to the left. So, the charge must move in a direction parallel (same as left) or antiparallel (opposite to left, i.e., right) to the magnetic field to have $\theta = 0^\circ$ or $180^\circ$ (so $\sin\theta = 0$ and thus $F = 0$). Directions like up, down, into the screen, or out of the screen are perpendicular (or at some non - 0, 180 angle) to the left - pointing magnetic field, so $\sin\theta = 1$ (or some non - zero value) and the force will be non - zero.

Answer:

left, right