An electron is moving in the north direction. It experiences a force in vertically upward direction. The magnetic field at the position of the electron is in the direction of

An electron enters a region where magnetic $(B)$ and electric $(E)$ fields are mutually perpendicular to one another, then

An electron enters a magnetic field whose direction is perpendicular to the velocity of the electron. Then

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

In a certain region static electric and magnetic fields exist. The magnetic field is given by $\vec B = {B_0}\left( {\hat i + 2\hat j - 4\hat k} \right)$. If a test charge moving with a velocity $\vec v = {v_0}\left( {3\hat i - \hat j + 2\hat k} \right)$ experiences no force in that region, then the electric field in the region, in $SI\, units$, is

Give features of force on charge particle inside magnetic field.