Question
Two parallel plate capacitors of capacity $C$ and $3\,C$ are connected in parallel combination and charged to a potential difference $18\,V$. The battery is then disconnected and the space between the plates of the capacitor of capacity $C$ is completely filled with a material of dielectric constant $9$. The final potential difference across the combination of capacitors will be $V$

Answer

Initial charge on $C =18\,CV$

initial charge on $3 C =54\,CV$

Let final common potential difference $= V ^{\prime}$

$9\,CV ^{\prime}+3\,CV ^{\prime}=18\,CV +54\,CV$

$12\,CV ^{\prime}=72\,CV \Rightarrow V ^{\prime}=6 V$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A ball is thrown vertically downwards from a height of  $20\, m$ with an initial velocity $v_0$, It collides with the ground, loses $50$ percent of its energy in collision and rebounds same height. The initial velocity $v_0..............\mathrm{ms}^{-2} ($Take $g=10 \,ms^{-2})$
Consider an infinite matrix of capacitors as shown in the figure. The effective capacitance between point $A$ and $B$ will be
Select the correct statement
The ammeter has range $1\, ampere$ without shunt. the range can be varied by using different shunt resistances. The graph between shunt resistance and range will have the nature
Which of the following compounds ($i$ through $v$) should not be classified as an acetal ?
For moving ball of cricket, the correct statement about de-Broglie wavelength is
The charges on two sphere are $+7\,\mu C$ and $-5\,\mu C$ respectively. They experience a force $F$. If each of them is given and additional charge of $-2\,\mu C$, the new force of attraction will be
The give graph shown variation (with distance $r$ from centre) of
For designing a voltmeter of range $50\,V$ and an ammeter of range $10\,mA$ using a galvanometer which has a coil of resistance $54\,\Omega$ showing a full scale deflection for $1\,mA$ as in figure.

$(A)$ for voltmeter $R \approx 50\,k\Omega$

$(B)$ for ammeter $r \approx 0.2\,\Omega$

$(C)$ for ammeter $r \approx 6\,\Omega$

$(D)$ for voltmeter $R \approx 5\,k \Omega$

$(E)$ for voltmeter $R \approx 500 \Omega$

Choose the correct answer from the options given below

A small solid ball is dropped from a height above the free surface of a liquid. It strikes the surface of the liquid at $t = 0$. The density of the material of the ball is $500\  kg/m^3$ and that of liquid is $1000\  kg/m^3$ If the ball comes momeritariiy at rest at $t = 2\  sec$ then initial height of the ball from surface of liquid was ..... $m$ (neglect viscosity)