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

Two parallel beams of protons and electrons, carrying equal currents are fixed at a separation $d$. The protons and electrons move in opposite directions. $P$ is a point on a line joining the beams, at a distance $x$ from any one beam. The magnetic field at $P$ is $B$. If $B$ is plotted against $x$, which of the following best represents the resulting curve

A charged particle enters a uniform magnetic field with velocity vector making an angle of $30^o$ with the magnetic field. The particle describes a helical trajectory of pitch $x$ . The radius of the helix is

An electron, moving along the $x-$ axis with an initial energy of $100\, eV$, enters a region of magnetic field $\vec B = (1.5\times10^{-3}T)\hat k$ at $S$ (See figure). The field extends between $x = 0$ and $x = 2\, cm$. The electron is detected at the point $Q$ on a screen placed $8\, cm$ away from the point $S$. The distance $d$ between $P$ and $Q$ (on the screen) is :......$cm$ (electron's charge $= 1.6\times10^{-19}\, C$, mass of electron $= 9.1\times10^{-31}\, kg$)

The radius of circular path of an electron when subjected to a perpendicular magnetic field is

$OABC$ is a current carrying square loop an electron is projected from the centre of loop along its diagonal $AC$ as shown. Unit vector in the direction of initial acceleration will be