$A$ beam of electrons and protons move parallel to each other in the same direction. Then they:

Two protons move parallel to each other,keeping a distance $r$ between them,both moving with the same velocity $\vec{v}$. Then the ratio of the electric force to the magnetic force of interaction between them is:

$A$ particle of charge $q$ and mass $m$ is moving along the $x$-axis with a velocity $v$ and enters a region of electric field $E$ and magnetic field $B$ as shown in the figures below. For which figure may the net force on the charge be zero?

Consider a current-carrying wire as shown in the figure. If the radius of the curved part of the wire is $R$ and the linear parts are assumed to be very long, then the magnetic induction of the field at the point $O$ is

$A$ proton moving with a constant velocity passes through a region of space without any change in its velocity. If $\overrightarrow{E}$ and $\overrightarrow{B}$ represent the electric and magnetic fields respectively,then this region of space may have

$A$ charged particle moves with constant velocity in a region where no effect of gravity is felt, but an electrostatic field $\vec{E}$ together with a magnetic field $\vec{B}$ may be present. Which of the following cases are possible?