Question 257: Magnetism and Matter

Question

Two long conductors, separated by a distance $d$ carry current ${I_1}$ and ${I_2}$ in the same direction. They exert a force $F$ on each other. Now the current in one of them is increased to two times and its direction is reversed. The distance is also increased to $3d$. The new value of the force between them is

Accepted Answer

Force between two long conductor carrying current,
$F = {{{\mu _0}} \over {4\pi }}{{2{I_1}{I_2}} \over d} 	imes \ell $
$F' =  - {{{\mu _0}} \over {4\pi }}{{2\left( {2{I_1}} ight){I_2}} \over {3d}}\ell $
$	herefore$ ${{F'} \over F} = {{ - 2} \over 3}$

Answer

$ - {{2F} \over 3}$

Answer

${F \over 3}$

Answer

$-2F$

Answer

$ - {F \over 3}$

Magnetism and Matter

Choose the correct answer: