Moving Charges ...

Two parallel wires carry currents of 20 A and 40 A in opposite directions. Another wire carrying a current antiparallel to 20 A is placed midway between the two wires. The magnetic force on it will be 

A conducting rod $$MN$$ of mass $$'m$$ and length $$'\ell '$$ is placed on parallel smooth conducting rails connected to an uncharged capacitor of capacitance $$'C'$$ and a battery of emf $$\varepsilon $$ as shown. A uniform magnetic field $$'B'$$ is existing perpendicular to the plane of the rails.The steady state velocity acquired by the conducting rod $$MN$$ after closing switch $$S$$ is (neglect the resistance of the parallel rails and the conducting rod )

A magnetic field is applied at perpendicular to the axis of cylinderical discharge tube then cathode and positive rays deflected in

If two streams of electrons move parallel to each other in same direction then they.

Two infinitely long parallel wires carrying current of 3A and 5A placed in the same plane at a distance of 2 m. The magnetic forces on 5 cm segment of wire A is:

Two parallel wire carrying current in opposite direction  

One gram hydrogen has $$6\times 10^{23}$$ atoms. Imagine that all the nuclei are put at the north pole of the earth and the electrons at the south pole of the earth (radius=6400 km). The force between the charges is

Two parallel wire carries current $$I_1$$ and $$I_2$$ are separated by distance $$d$$. Force per unit length of wire is $$F$$.
Then :

A charged particle enters a magnetic field at right angles to the magnetic filed as shown in figure. the field exits for a length equal to $$1.25$$ times the radius of circular path of the particle. the deviation of the particle is 

The charge on a particle is $$100$$ times that of electron. It is revolving in a circular path of radius $$0.8 \mathrm { m }$$ at a frequency of $$10 ^ {  th  }$$ revolutions per second. The magnetic field at the centre of path will be -