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STD 12 - 2. Electric potential and capacitance — JEE STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceJEESTD 12 - 2. Electric potential and capacitance4 Marks
MCQ
A composite parallel plate capacitor is made up of two different dielectric materials with different thickness $\left(t_{1}\right.$ and $\left.t_{2}\right)$ as shown in figure. The two different dielectric material are separated by a conducting foil $F$. The voltage of the conducting foil is $.....V$
  • A
    $6$
  • B
    $66$
  • C
    $600$
  • ✓
    $60$
✓

Answer

Correct option: D.
$60$
d
Capacitance of each capacitor

$C _{1}=\frac{ A 3 \epsilon_{0}}{\frac{1}{2}}=6 A \epsilon_{0}$

$C _{2}= A 4 E _{0}=4 A \in_{0}$

Equivalent capacitance

$C _{\text {eq }}=\frac{ C _{1} C _{2}}{ C _{1}+ C _{2}} \Rightarrow \frac{24}{10} A \in_{0}$

$q _{\text {net }}= C _{\text {eq }}(\Delta V ) \Rightarrow 240 A \in_{0}$

$\Delta V _{2}=\frac{240 A \epsilon_{0}}{4 A \epsilon_{0}}=60\,V$

$\left(\Delta V _{2}=\text { Potential drop across } C _{2}\right)$

$V _{\text {foil }}=60\,V$

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