A charge $q$ is moving in a magnetic field then the magnetic force does not depend upon

Show that a force that does no work must be a velocity dependent force.

A uniform beam of positively charged particles is moving with a constant velocity parallel to another beam of negatively charged particles moving with the same velocity in opposite direction separated by a distance $d.$ The variation of magnetic field $B$ along a perpendicular line draw between the two beams is best represented by

If an electron is going in the direction of magnetic field $\overrightarrow B $ with the velocity of $\overrightarrow {v\,} $ then the force on electron is

A charged particle enters a magnetic field $H$ with its initial velocity making an angle of $45^\circ $ with $H$. The path of the particle will be

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