If the direction of the initial velocity of the charged particle is perpendicular to the magnetic field, then the orbit will be   or  The path executed by a charged particle whose motion is perpendicular to magnetic field is

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. If the direction of the magnetic field is along the outward normal to the plane of the paper, then the time spent by the particle in the region of the magnetic field after entering it at $C$ is nearly :-......$ns$

An electron is projected with uniform velocity along the axis inside a current carrying long solenoid. Then :

The figure shows three situations when an electron with velocity $\vec v$ travels through a nuniform magnetic field $\vec B$ . In each case, what is the direction of magnetic force on the electron?

Write Lorentz force equation.

Which law is useful to determine relation between current and magnetic fields due to it.