For the magnetic field to be maximum due to a small element of a current-carrying conductor at a point,the angle between the element and the line joining the element to the given point must be.......$^o$

Magnetic field at a distance $r$ from an infinitely long straight conductor carrying a steady current varies as

$A$ straight conductor carrying current $i$ splits into two parts as shown in the figure. The radius of the circular loop is $R$. The total magnetic field at the centre $P$ of the loop is

Do magnetic forces obey Newton's third law? Verify for two current elements $\overrightarrow{dl_1} = dl(\hat{i})$ located at the origin and $\overrightarrow{dl_2} = dl(\hat{j})$ located at $(0, R, 0)$. Both carry current $I$.

An electric current passes through a long straight wire. At a distance $5 \ cm$ from the wire,the magnetic field is $B$. The magnetic field at $20 \ cm$ from the wire would be:

$A$ thin circular frame of radius $a$ is made of insulating material. $A$ square loop is constructed within it. If the loop carries current $I$,then the magnetic induction at the geometrical centre $O$ will be: