Electrostatic Potential and Capacitance - Result Question 43
«««< HEAD:content/english/neet-pyq-chapterwise/physics/electrostatic-potential-and-capacitance/electrostatic-potential-and-capacitance-result-question-43.md
45. A parallel plate condenser with oil between the plates (dielectric constant of oil $K=2$ ) has a capacitance $C$. If the oil is removed, then capacitance of the capacitor becomes
======= ####45. A parallel plate condenser with oil between the plates (dielectric constant of oil $K=2$ ) has a capacitance $C$. If the oil is removed, then capacitance of the capacitor becomes
3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed:content/english/neet-pyq-chapterwise/physics/electrostatic-potential-and-capacitance/electrostatic-potential-and-capacitance—result-question-43.md (a) $\sqrt{2} C$
(b) $2 C$
(c) $\frac{C}{\sqrt{2}}$
(d) $\frac{C}{2}$
[1999, 97]
Show Answer
Answer:
Correct Answer: 45. (d)
Solution:
- (d) When oil is placed between space of plates
$C=\frac{2 A \varepsilon_0}{d} \ldots$ (1) $[\because C=\frac{K A \varepsilon_0}{d}.$, if $.K=2]$
When oil is removed $C^{\prime}=\frac{A \varepsilon_0}{d}$
On comparing both equations, we get $C^{1}=C / 2$
When dielectric is partially filled between the plates of a parallel plate capacitor then its capacitance increases but potential difference decreases. To maintain the capacitance and potential difference of capacitor as before separatoin betweeen the plates has to be increased by d. In such case
$ k=\frac{t}{t-d} \text{ (Here, } t=\text{ seperation between plates.) } $
