A beam of ions with velocity $2 \times {10^5}\,m/s$ enters normally into a uniform magnetic field of $4 \times {10^{ – 2}}\,tesla$. If the specific charge of the ion is $5 \times {10^7}\,C/kg$, then the radius of the circular path described will be…….$m$

An $\alpha -$ particle of $1\,MeV$ energy moves on circular path in uniform magnetic field. Then kinetic energy of proton in same magnetic field for circular path of double radius is……$MeV$

Explain electric field and its source as well as magnetic field and its source.

An electric field of $1500\, V / m$ and a magnetic field of $0.40\, weber / meter^2$ act on a moving electron. The minimum uniform speed along a straight line the electron could have is

A particle of mass $0.6\, g$ and having charge of $25\, nC$ is moving horizontally with a uniform velocity ${\rm{1}}{\rm{.2}} \times {\rm{1}}{{\rm{0}}^{\rm{4}}}\,m{s^{ – 1}}$ in a uniform magnetic field, then the value of the magnetic induction is $(g = 10\,m{s^{ – 2}})$