Two conducting spheres of radii $r_1$ and $r_2$ are charged to the same surface charge density. The ratio of electric fields near their surfaces is

Two point charges $-5 \mu C$ and $+5 \mu C$ are placed at $A$ and $B$ respectively on a straight line separated by $5 \ cm$. At a point $C$,if the resultant electric field is parallel to the line joining the points $A$ and $B$,then:

$A$ thin conducting ring of radius $R$ is given a charge $+Q.$ The electric field at the centre $O$ of the ring due to the charge on the part $AKB$ of the ring is $E.$ The electric field at the centre due to the charge on the part $ACDB$ of the ring is

The figure shows some electric field lines corresponding to an electric field. Then:

$A$ negative charge is placed at the centre of a non-conducting sphere. The direction of the electric field at any point on the surface of the sphere is

Two point charges $q_{1}$ and $q_{2},$ of magnitude $+10^{-8} \; C$ and $-10^{-8} \; C,$ respectively,are placed $0.1 \; m$ apart. Calculate the electric fields at points $A, B$ and $C$ shown in the figure.