A $10 \;eV$ electron is circulating in a plane at right angles to a uniform field at magnetic induction $10^{-4} \;W b / m^{2}(=1.0$ gauss), the orbital radius of electron is …….. $cm$

If a charged particle enters perpendicularly in the uniform magnetic field then

Two identical charged particles enter a uniform magnetic field with same speed but at angles $30^o$ and $60^o$ with field. Let $a, b$ and $c$ be the ratio of their time periods, radii and pitches of the helical paths than

A particle of mass $m = 1.67 \times 10^{-27}\, kg$ and charge $q = 1.6 \times 10^{-19} \, C$ enters a region of uniform magnetic field of strength $1$ $tesla$ along the direction shown in the figure. The speed of the particle is $10^7\, m/s.$ The magnetic field is directed along the inward normal to the plane of the paper. The particle enters the field at $C$ and leaves at $D.$ Then the angle $\theta$ must be :-………$^o$

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 $(g = 10\,m{s^{ – 2}})$