$A$ and $B$ are concentric conducting spherical shells. $A$ is given a positive charge while $B$ is earthed. Then :-
Medium
Download our app for free and get startedPlay store
The charge on sphere $B$ due to ground potential of zero is $-Q$ on the inner surface. Charge density on $A$ is $Q / 4 \pi r_{A}^{2}$ and that of $B$ is $-Q / 4 \pi r_{B}^{2} .$ So two charge densities are not equal.

option $A$ is incorrect.

The two sphere system act as the concentric sphere capacitor.

By Gauss'law, The electric field is zero inside $A$ and outside the $B$.

But it is $non-zero$ between $A$ and $B$.

So option $\mathrm{B}$ and $\mathrm{D}$ are incorrect.

option $C$ is incorrect.

art

Download our app
and get started for free

Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*

Similar Questions

  • 1
    A parallel plate capacitor with area $200\,cm^2$ and separation between the plates $1.5\,cm$, is connected across a battery of $emf$ $V$. If the force of attraction between the plates is $25\times10^{-6}\,N$, the value of $V$ is approximately........$V$ $\left( {{\varepsilon _0} = 8.85 \times {{10}^{ - 12}}\,\frac{{{C^2}}}{{N{m^2}}}} \right)$
    View Solution
  • 2
    An electric dipole of moment $p$ is placed in an electric field of intensity $E.$ The dipole acquires a position such that the axis of the dipole makes an angle $\theta$ with the direction of the field. Assuming that the potential  energy of the dipole to be zero when $\theta = 90^o$ , the torque and the potential energy of the dipole will respectively be
    View Solution
  • 3
    $A, B$ and $C$ are three points in a uniform electric field. The electric potential is
    View Solution
  • 4
    Consider a spherical shell of radius $R$ with a total charge $+ Q$ uniformly spread on its surface (centre of the shell lies at the origin $x=0$ ). Two point charges $+q$ and $-q$ are brought, one after the other from far away and placed at $x=-a / 2$ and $x=+a / 2( < R)$, respectively. Magnitude of the work done in this process is 
    View Solution
  • 5
    As shown in the figure, two parallel plate capacitors having equal plate area of $200\,cm ^2$ are joined in such a way that $a \neq b$. The equivalent capacitance of the combination is $x \varepsilon_0 F$. The value of $x$ is $..........$.
    View Solution
  • 6
    A capacitor of capacitance $C_1 = 1\ \mu F$ can with stand maximum voltage $V_1= 6\ kV$ (kilo-volt) and another capacitor of capacitance $ C_2 = 3\ \mu F$ can withstand maximum voltage $V_2 = 4\  kV$. When the two capacitors are connected in series, the combined system can withstand a maximum voltage of......$kV$
    View Solution
  • 7
    A parallel plate capacitor is formed by two plates each of area $30 \pi\, cm ^{2}$ separated by $1\, mm$. A material of dielectric strength $3.6 \times 10^{7} \,Vm ^{-1}$ is filled between the plates. If the maximum charge that can be stored on the capacitor without causing any dielectric breakdown is $7 \times 10^{-6}\, C$, the value of dielectric constant of the material is

    $\left\{ Use : \frac{1}{4 \pi \varepsilon_{0}}=9 \times 10^{9} Nm ^{2} C ^{-2}\right\}$

    View Solution
  • 8
    Two concentric spherical shells of radius $R_1$ and $R_2$ have $q_1$ and $q_2$ charge respectively as shown in figure. How much charge will flow through key $k$ when it is closed
    View Solution
  • 9
    Two plates are at potentials $-10\, V$ and $+30\, V$. If the separation between the plates be $2\, cm$. The electric field between them is.......$V/m$
    View Solution
  • 10
    $64$ drops each having the capacity $C$ and potential $V$ are combined to form a big drop. If the charge on the small drop is $q$, then the charge on the big drop will be
    View Solution