Two charged particles, each with a charge of $+q$, are located along the $x$-axis at $x = 2$ and $x = 4$, as shown below. Which of the following shows the graph of the magnitude of the electric field along the $x$-axis from the origin to $x = 6$?

$A$ circular wire loop of radius $1 \, cm$ carries a total charge $1 \times 10^{-6} \, C$ distributed uniformly over its length. If $0.01 \%$ of its length (circumference) is cut off, then the electric field at the centre of the loop due to the remaining wire is
$(\text{Take} \, \frac{1}{4 \pi \varepsilon_0}=9 \times 10^9 \, \text{SI unit})$

Two non-conducting spheres of radii $R_1$ and $R_2$ and carrying uniform volume charge densities $+\rho$ and $-\rho$,respectively,are placed such that they partially overlap,as shown in the figure. At all points in the overlapping region:
$(A)$ the electrostatic field is zero
$(B)$ the electrostatic potential is constant
$(C)$ the electrostatic field is constant in magnitude
$(D)$ the electrostatic field has same direction

$A$ charge produces an electric field of $1\, N/C$ at a point distant $0.1\, m$ from it. The magnitude of the charge is:

The electric field lines on the left have twice the separation of those on the right as shown in the figure. If the magnitude of the electric field at $A$ is $40 \ Vm^{-1}$,what is the force on a $20 \ \mu C$ charge kept at $B$?

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