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 $\rho _0$ is a constant. The electric field at an internal point $(r < R)$ is
$\frac{{{\rho _0}}}{{4{\varepsilon _0}}}\left( {\frac{r}{3} - \frac{{{r^2}}}{{4R}}} \right)$
$\frac{{{\rho _0}}}{{{\varepsilon _0}}}\left( {\frac{r}{3} - \frac{{{r^2}}}{{4R}}} \right)$
$\frac{{{\rho _0}}}{{3{\varepsilon _0}}}\left( {\frac{r}{3} - \frac{{{r^2}}}{{4R}}} \right)$
$\frac{{{\rho _0}}}{{12{\varepsilon _0}}}\left( {\frac{r}{3} - \frac{{{r^2}}}{{4R}}} \right)$
An infinitely long solid cylinder of radius $R$ has a uniform volume charge density $\rho$. It has a spherical cavity of radius $R / 2$ with its centre on the axis of the cylinder, as shown in the figure. The magnitude of the electric field at the point $P$, which is at a distance $2 \ R$ from the axis of the cylinder, is given by the expression $\frac{23 \rho R }{16 k \varepsilon_0}$. The value of $k$ is
A solid metallic sphere has a charge $ + \,3Q$. Concentric with this sphere is a conducting spherical shell having charge $ - Q$. The radius of the sphere is $a$ and that of the spherical shell is $b(b > a)$. What is the electric field at a distance $R(a < R < b)$ from the centre
An isolated sphere of radius $R$ contains uniform volume distribution of positive charge. Which of the curve shown below, correctly illustrates the dependence of the magnitude of the electric field of the sphere as a function of the distance $r$ from its centre?
A conducting sphere of radius $R = 20$ $cm$ is given a charge $Q = 16\,\mu C$. What is $\overrightarrow E $ at centre
A long charged cylinder of linear charged density $\lambda$ is surrounded by a hollow co-axial conducting cylinder. What is the electric field in the space between the two cylinders?