An electron is travelling in east direction and a magnetic field is applied in upward direction then electron will deflect in

A negatively charged particle projected towards east is deflected towards north by a magnetic field. The field may be

If a proton enters perpendicularly a magnetic field with velocity $v$, then time period of revolution is $T$. If proton enters with velocity $2 v$, then time period will be

A charged particle enters a uniform magnetic field perpendicular to it. The magnetic field

A particle of charge $16\times10^{-16}\, C$ moving with velocity $10\, ms^{-1}$ along $x-$ axis enters a region where magnetic field of induction $\vec B$ is along the $y-$ axis and an electric field of magnitude $10^4\, Vm^{-1}$ is along the negative $z-$ axis. If the charged particle continues moving along $x-$ axis, the magnitude of $\vec B$ is

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