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Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsElectrostatic Potential and Capacitance2 Marks
Question
A parallel plate capacitor with air between the plates has a capacitance of 8 pF. The separation between the plates is now reduced by half and the space between them is filled with a medium of dielectric constant 5. Calculate the value 
of capacitance of the capacitor in the second case.
✓

Answer

$\text{c} =\frac{\text{A}\varepsilon_{\circ}\varepsilon_{r}}{\text{d}}$ or $\frac{\text{k}\varepsilon_{\circ}\text{A}}{\text{d}}$$\text{c} = 5\times\frac{\varepsilon_{\circ}\text{A}}{\text{d}/2}$
$\text{c} = 10 \bigg(\frac{\text{A}\varepsilon_{\circ}}{\text{d}}\bigg) = 10 \times8 = 80\text{pf}$.

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