Through two parallel wires $A$ and $B$, $10$ and $2$ $ampere$ of currents are passed respectively in opposite direction. If the wire $A$ is infinitely long and the length of the wire $B$ is $ 2\, m$, the force on the conductor $B$, which is situated at $10\, cm$ distance from $A$ will be

A long straight wire carrying current of $25$ $\mathrm{A}$ rests on a table as shown in figure. Another wire $\mathrm{PQ}$ of length $1$ $\mathrm{m}$, mass $2.5$ $\mathrm{g}$ carries the same current but in the opposite direction. The wire $\mathrm{PQ}$ is free to slide up and down. To what height will $\mathrm{PQ}$ rise ? 

In figure the cube is of $40\,\, cm$ edge. Four straight segment of wire $ab, bc, cd$ and $da$ form a  closed loop that carries a current $I = 5\,A$. A uniform magnetic field $0.02\,\,T$ is in $+y\,-$ direction  ratio of magnetic force on segement $ab$  and $bc$  is

A winding wire which is used to frame a solenoid can bear a maximum $10\, A$ current. If length of solenoid is $80\,cm$ and it's cross sectional radius is $3\, cm$ then required length of winding wire is $(B = 0.2\,T)$

Find force per unit length at $P$.

A vertical wire carrying a current in the upward direction is placed in horizontal magnetic field directed towards north. The wire will experience a force directed towards