Tag: capacitance

Questions Related to capacitance

A Parallel platecapacitor made of circular plates each of radius $R=6.0cm$ has a capacitance 100$\mathrm { pF }$ is connected to 230$\mathrm { V }$ of $\mathrm { AC }$ supply of 300 rad/sec.frequency. The rms value of displacement current

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. $6.9\mu A$

  2. $2.3\mu A$

  3. $9.2\mu A$

  4. $4.6\mu A$

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Correct Option: A
Explanation:

Given$:-$

$R=6.0cm$
$C = 100pF$
$ = 100 \times {10^{ - 12}}F$
$w = 300\,rad/s$
${I _{rms}} = 230 \times 300 \times 100 \times {10^{ - 12}}$
$ = 6.9 \times {10^{ - 9}}$
$ = 6.9\mu A$
Hence, 
option $(A)$ is correct answer.

Two parallel plates have equal and opposite charge. When the space between them is evacuated. the electric field between the plates $2 \times {10^5}\,V/m.$ When the space is filed with dielectric the electric field becomes ${10^5}\,V/m$ The dielectric constant of he dielectric material is 

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. $2$

  2. $4$

  3. $5$

  4. $9$

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Correct Option: A
Explanation:

Dielectric constant$:-$

$K = \dfrac{{{E _0}}}{E}$
$ = \dfrac{{2 \times {{10}^5}}}{{1 \times {{10}^5}}} = 2$
Hence,
option $(A)$is correct answer

3 identical capacitor are joined in parallel and are charged with a battery of 10V. now the battery is removed and they are joined in series with each other. in this condition what would be the potential difference between the free plates in combination?

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. $10V$

  2. $30V$

  3. $\frac {10}{3}$

  4. $60V$

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Correct Option: C

Two capacitors of capacitance $2\, \mu F$ and $4\, \mu F$ are charge to $200\, V$ and $100\, V$ respectively. They are then connected in parallel to each other. What is the potential across each capacitor ?

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. $116\, V$

  2. $133\, V$

  3. $148\, V$

  4. $164\, V$

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Correct Option: B

A parallel plate capacitor has a capacity C.If a thin metal plate (M) joins the two coating A and B of the capacitor,its new capacitance is

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. 2 C

  2. C / 2

  3. Zero

  4. Infinity

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Correct Option: C

A capacitor is charged by a battery. the battery is removed and another identical uncharged capacitor is connected in parallel. the total electromagnetic energy of resulting system

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. Decrease by a factor of 2

  2. remains the same

  3. increase by a factor of 2

  4. increase by a factor 4

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Correct Option: A

A parallel plate air capacitor has capacity 'C', a distance of separation between plate is 'd' and potential difference 'V' is applied between the plates. Force of attraction between the plates of the parallel plate air capacitor is:

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. $\dfrac{{C{V^2}}}{{2d}}$

  2. $\dfrac{{C{V^2}}}{{d}}$

  3. $\dfrac{{{C^2}{V^2}}}{{2{d^2}}}$

  4. $\dfrac{{{C^2}{V^2}}}{{{d^2}}}$

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Correct Option: A

The distance between the plates of a parallel plate capacitor is $1\ mm$. What must be the area of the plate of the capacitor if the capacitance is to be $1.0\mu F$?

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. $102.5\ m^{2}$

  2. $205.9\ m^{2}$

  3. $112.9\ m^{2}$

  4. $302.9\ m^{2}$

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Correct Option: A

Two parallel plate capacitor of capacitances C and 2C are conncected in parallel and changed to a potential difference V.If  the bsttery is disconnected and the space between the plate of the capacitor of cpacince c is cpmpletely  filled with a metrial of dielectric constant K, then the potential difference a cross the capacitor will be come

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. $3V\left( {K + 2} \right)$

  2. $\left( {\frac{{K + 2}}{{3V}}} \right)$

  3. $\left( {\frac{{3V}}{{K + 2}}} \right)$

  4. $\frac{{3\left( {K + 2} \right)}}{V}$

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Correct Option: C

A parallel plate capacitor has circular plates of $8.0\ cm$ radius and are separated by $1.0\ mm$. Calculate the capacitance.

physics capacitance capacitors in parallel combination of capacitors capacitors in parallel and series

  1. $120\ pF$

  2. $140\ pF$

  3. $160\ pF$

  4. $180\ pF$

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Correct Option: D