Kerala KEAM 5 June 2024 Solved Paper

When a charged particle enters a magnetic field, the motion of the particle is influenced by the Lorentz force, which is given by:$$F = q(\mathbf{v} \times \mathbf{B})$$Where:- $q$ is the charge of the particle,- $\mathbf{v}$ is the velocity of the particle,- $\mathbf{B}$ is the magnetic field.The force $F$ is perpendicular to the velocity $v$, so the particle will follow a circular path due to the magnetic force. However, when the velocity $v$ has a component along the magnetic field $B$, this component of the velocity does not experience any magnetic force because the magnetic force is perpendicular to both the velocity and the magnetic field.Thus, the particle will:- Move in a circular path due to the component of velocity perpendicular to $B$,- Move in a straight line along the direction of the component of velocity parallel to $B$.The combination of these two motions results in a helical path.Therefore, the correct answer is:$$\boxed{D) A helical path}$$ Quick Tip: When a charged particle has a component of velocity along the magnetic field, it follows a helical path, with the motion perpendicular to the magnetic field forming a circle, and the parallel component causing linear motion along the field.