An electron is moving on a circular path of radius $r$ with speed $v$ in a transverse magnetic field $B$. $e/m$ for it will be

Write Lorentz force equation.

Which particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field

A charged particle of mass $m$ and charge $q$ describes circular motion of radius $r$ in a uniform magnetic field of strength $B$. The frequency of revolution is

A particle is projected with a velocity ( $10\ m/s$ ) along $y-$ axis from point $(2, 3)$ . Magnetic field of $\left( {3\hat i + 4\hat j} \right)$ Tesla exist uniformly in the space. Its speed when particle passes through $y-$ axis for the third time is : (neglect gravity)

An electron of mass $m$ and charge $q$ is travelling with a speed $v$ along a circular path of radius $r$ at right angles to a uniform of magnetic field $B$. If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of