In the circuit shown here $C_1 = 6\,\mu F, C_2 = 3 \,\mu F$ and battery $B = 20\,V$. The switch $S_1$ is first closed. It is then opened and afterwards $S_2$ is closed. What is the charge (in $\mu F$)finally on $C_2$ ?
Medium
Download our app for free and get startedPlay store
Initial charge on $C_{1}$ is $q=C_{1} V_{B}=6 \times 10^{-6} \times 20$

$=120\, \mu \mathrm{C}$

Now when $S_{2}$ closed, suppose common potential $=$ $\mathrm{V}$

charge on $\mathrm{C}_{1}=\mathrm{q}_{1}$

and charge on $\mathrm{C}_{2}=\mathrm{q}_{2}$

So, $ \mathrm{q}_{1}=\mathrm{C}_{1} \mathrm{V}$ and $\mathrm{q}_{2}=\mathrm{C}_{2} \mathrm{V}$

$\frac{\mathrm{q}_{1}}{\mathrm{q}_{2}}=\frac{\mathrm{C}_{1}}{\mathrm{C}_{2}} \Rightarrow \frac{\mathrm{q}_{1}}{\mathrm{q}_{2}}=\frac{6}{3}=2 \Rightarrow \mathrm{q}_{1}=2 \mathrm{q}_{2}$

Also $\mathrm{q}_{1}+\mathrm{q}_{2}=\mathrm{q} \Rightarrow 2 \mathrm{q}_{2}+\mathrm{q}_{2}=\mathrm{q}$

$\Rightarrow \mathrm{q}_{2}=\frac{\mathrm{q}}{3}=\frac{120 \times 10^{-6}}{3}$

$=40\, \mu \mathrm{C}$

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
    Four metallic plates arearranged as shown in the figure. If the distance between each plate then capacitance of the given system between points $A$ and $B$ is (Given $d < < A$)
    View Solution
  • 2
    For changing the capacitance of a given parallel plate capacitor, a dielectric material of dielectric constant $K$ is used, which has the same area as the plates of the capacitor. The thickness of the dielectric slab is $\frac{3}{4} d$, where $'d'$ is the separation between the plates of parallel plate capacitor. The new capacitance $(C')$ in terms of original capacitance $\left( C _{0}\right)$ is given by the following relation
    View Solution
  • 3
    The electric potential $V(x, y, z)$ for a planar charge distribution is given by: 

    $V\left( {x,y,z} \right) = \left\{ {\begin{array}{*{20}{c}}
    {0\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,for\,x\, < \, - d}\\
    { - {V_0}{{\left( {1 + \frac{x}{d}} \right)}^2}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,for\, - \,d\, \le x < 0}\\
    { - {V_0}\left( {1 + 2\frac{x}{d}} \right)\,\,\,\,\,\,\,\,\,\,\,for\,0\, \le x < d}\\
    { - 3{V_0}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,for\,x\, > \,d}
    \end{array}} \right.$

    where $-V_0$ is the potential at the origin and $d$ is a distance. Graph of electric field as a function of position is given as

    View Solution
  • 4
    The electric potential at the surface of an atomic nucleus $(Z = 50)$ of radius $9.0×{10^{ - 13}}\, cm$ is
    View Solution
  • 5
    The electric potential at a point on the axis of an electric dipole depends on the distance $r$ of the point from the dipole as
    View Solution
  • 6
    A positive point charge is released from rest at a distance $r_0$ from a positive line charge with uniform density. The speed $(v)$ of the point charge, as a function of instantaneous distance $r$ from line charge, is proportional to
    View Solution
  • 7
    In the circuit shown in figure, four capacitors are connected to a battery. The maximum energy is stored in the capacitor of.....$\mu F$
    View Solution
  • 8
    The distance between the circular plates of a parallel plate condenser $40\,mm$ in diameter, in order to have same capacity as a sphere of radius $1\;metre$ is....$mm$
    View Solution
  • 9
    For shown situation, in steady state condition ratio of charge stored in the first and last $n^{th}$ capacitor is
    View Solution
  • 10
    The equivalent capacitance in the circuit between $A$ and $B$ will be.....$\mu \,F$
    View Solution