A uniform electric field and a uniform magnetic field are produced, pointed in the same direction. An electron is projected with its velocity pointing in the same direction

A particle having charge of $1 \,\,C$, mass $1 \,\,kg$ and speed $1 \,\,m/s$ enters a uniform magnetic field, having magnetic induction of $1$ $T,$ at an angle $\theta = 30^o$ between velocity vector and magnetic induction. The pitch of its helical path is (in meters) 

An electron moving with a speed $u$ along the positive $x-$axis at $y = 0$ enters a region of uniform magnetic field $\overrightarrow B = - {B_0}\hat k$ which exists to the right of $y$-axis. The electron exits from the region after some time with the speed $v$ at co-ordinate $y$, then

A charged particle initially at rest at $O$,when released follows a trajectory as shown alongside. Such a trajectory is possible in the presence of

A charged particle moves with velocity $v$ in a uniform magnetic field $\overrightarrow B $. The magnetic force experienced by the particle is

Particles having positive charges occasionally come with high velocity from the sky towards the earth. On account of the magnetic field of earth, they would be deflected towards the