Assertion (A): A charged particle is moving with velocity v in x - y plane, making an angle θ(0<θ<(π)/2) with x -axis. If a uniform magnetic field B…

Assertion (A) : A charged particle is moving with velocity v in $\displaystyle \mathrm{x}-\mathrm{y}$ plane, making an angle $\displaystyle \theta\left(0<\theta<\frac{\pi}{2}\right)$ with $\displaystyle \mathrm{x}$-axis. If a uniform magnetic field $\displaystyle \overrightarrow{\mathrm{B}}$ is applied in the region, along $\displaystyle \mathrm{y}$-axis, the particle will move in a helical path with its axis parallel to x -axis. Reason $\displaystyle (R)$ : The direction of the magnetic force acting on a charged particle moving in a magnetic field is along the velocity of the particle.