Moving Charges ...

In case Hall effect for a strip having charge $$Q$$ and area of cross-section $$A$$, the Lorentz force is

" On flowing current in a conducting wire the magnetic field produces around it". It is a law of 

Mixed $$He^+$$ and $$O^{2+}$$ ions (mass of $$He^+=4$$ amu and that of $$O^{2+}=16$$ amu) beam passes a region of constant perpendicular magnetic field. If kinetic energy of all the ions is same then

If cathode rays are projected at right angles to a magnetic field, their trajectory is

A beam of electrons and protons move parallel to each other in the same direction, then they

Three long, straight parallel wires carrying current, are arranged as shown in figure. The force experienced by a $$25\ cm$$ length of wire $$C$$ is

An electron and a proton have equal kinetic energies. They enter in a magnetic perpendicular. They 

Assertion : An electron is not deflected on passing through certain region of space. This observation confirms that there is no magnetic field in that region.
Reason : The deflection of electron depends on angle between velocity of electron and direction of magnetic field.

The distance between the supply wires of an electric-mains is $$12cm$$. These wires experience $$4mg$$ weight per unit length. Current flowing in both the wire will be if they carry current in same direction.

A long, vertical, metallic wire carries downward electric current.
What would be the direction of the field if the current consisted of positive charges moving downward instead of electrons moving upward?