JEE Mains · Physics · STD 12 - Electromagnetic waves
- JEE Mains 2025
- Medium
- Numerical
A parallel plate capacitor consisting of two circular plates of radius 10 cm is being charged by a constant current of 0.15 A . If the rate of change of potential difference between the plates is \(7 \times 10^8 \mathrm{~V} / \mathrm{s}\) then the integer value of the distance between the parallel plates is \(\left(\right.\) Take, \(\left.\epsilon_0=9 \times 10^{-12} \frac{\mathrm{~F}}{\mathrm{~m}}, \pi=\frac{22}{7}\right)\) ________ \(\mu \mathrm{m}\).
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) 1320
Step-by-step Solution
Detailed explanation
\(\begin{aligned}
& Q=c V \\
& V=\frac{Q}{c}=\frac{i t}{\left(\frac{\varepsilon_0 A}{d}\right)} \\
& d=\frac{\varepsilon_0 \pi r^2}{i}\left(\frac{v}{t}\right)
\end{aligned}\)
Putting values
\(\begin{aligned}
d & =\frac{9 \times 10^{-12} \times \frac{22}{7} \times(0.1)^2}{0.15} \times\left(7 \times 10^8\right) \\
& =1320 \mu \mathrm{~m}
\end{aligned}\)
& Q=c V \\
& V=\frac{Q}{c}=\frac{i t}{\left(\frac{\varepsilon_0 A}{d}\right)} \\
& d=\frac{\varepsilon_0 \pi r^2}{i}\left(\frac{v}{t}\right)
\end{aligned}\)
Putting values
\(\begin{aligned}
d & =\frac{9 \times 10^{-12} \times \frac{22}{7} \times(0.1)^2}{0.15} \times\left(7 \times 10^8\right) \\
& =1320 \mu \mathrm{~m}
\end{aligned}\)
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