Question

At a certain instant, a proton is moving in the positive x direction through a magnetic field in the negative z direction. What is the direction of the magnetic force exerted on the proton

Answer 1

Answer: positive y direction

Explanation:

we know that direction of velocity is in +x direction

now the magnetic force is in negative z direction

therefore the magnetic force , F = q × ( v × B)

F = ( i × [ - k ] ) direction

F = j direction

so the direction of the magnetic force on the proton is positive y direction.