$15$ charges, each of value $q$, are placed on the $X$-axis at an equal distance of $0.5R$. The electric flux associated with a spherical closed surface of radius $1.5R$, which has one of the charges at its center, is:

$A$ solid ball of radius $R$ has a charge density $\rho$ given by $\rho = \rho_0 \left( 1 - \frac{r}{R} \right)$ for $0 \leq r \leq R$. The electric field outside the ball is

In a uniformly charged sphere of total charge $Q$ and radius $R$,the electric field $E$ is plotted as a function of distance $r$ from the center. The graph which would correspond to the above is:

$A$ solid sphere of radius $r_1=1 \text{ cm}$ carries charge distributed uniformly over it with density $\rho_1=-3 \text{ C/cm}^3$. It is surrounded by a concentric spherical shell of radius $r_2=2 \text{ cm}$ carrying uniform charge density $\rho_2=0.5 \text{ C/cm}^3$. If $E_d$ denotes the magnitude of the electric field at distance $d$ from the common centre of the spheres,then

$A$ spherically symmetric charge distribution is characterised by a charge density having the following variations:
$\rho (r) = \rho_0 \left( 1 - \frac{r}{R} \right)$ for $r < R$
$\rho (r) = 0$ for $r \ge R$
Where $r$ is the distance from the centre of the charge distribution and $\rho_0$ is a constant. The electric field at an internal point $(r < R)$ is:

For an infinite line of charge having charge density $\lambda$ lying along the $x$-axis,the work required in moving a charge $q$ from point $C$ to point $A$ along the arc $CA$ is: