An electron having a charge e moves with a velocity $v$ in positive $x$ direction. A magnetic field acts on it in positive $y$ direction. The force on the electron acts in (where outward direction is taken as positive $z$-axis).

Fill the blank :

$(i)$ Static charge produces ...... field around it.(Electric, Magnetic)

$(ii)$ Moving charge produces ...... field around it.

An electron is moving along the positive $X$-axis. You want to apply a magnetic field for a short time so that the electron may reverse its direction and move parallel to the negative $X$-axis. This can be done by applying the magnetic field along

A proton (mass $m$ and charge $+e$) and an $\alpha - $particle (mass $4m$ and charge $+2e$) are projected with the same kinetic energy at right angles to the uniform magnetic field. Which one of the following statements will be true

An ion beam of specific charge $5 \times 10^7$ $coulomb/kg$ enter a uniform magnetic field of $4 \times 10^{-2}\, tesla$ with a velocity $2 \times 10^5\, m/s$ perpendicularly. The radius of the circular path of ions in meter will be

A proton of mass $1.67\times10^{-27}\, kg$ and charge $1.6\times10^{-19}\, C$ is projected with a speed of $2\times10^6\, m/s$ at an angle of $60^o$ to the $X-$ axis. If a uniform magnetic field of $0.104\, tesla$ is applied along the $Y-$ axis, the path of the proton is