Question 575: Electrostatics & Capacitance

Question

In the given figure potential at point 'A' is 900 volt and point 'B' is earthed. What will be the potential at point 'P' ?

Accepted Answer

Capacitors $$\mathrm{C}_2$$ and $$\mathrm{C}_3$$ are in parallel. Hence their equivalent capacitance
$$\mathrm{C}_4=\mathrm{C}_2+\mathrm{C}_3=8+4=12 \mu \mathrm{F}$$
$$\mathrm{C}_4$$ and $$\mathrm{C}_1$$ are in series.
Their equivalent capacitance $$\mathrm{C}=\frac{12 	imes 6}{12+6}=\frac{72}{18}=4 \mu \mathrm{F}$$
Charge stored by the combination
$$\mathrm{q}=\mathrm{CV}=4 	imes 900$$
$$=3600 \mu \mathrm{C}$$
In the series combination, change in same on each capacitor.
$$	herefore$$ Charge on $$\mathrm{C}_1=3600 \mu \mathrm{C}$$
$$P, D$$, across $$C_1$$ is $$V_1=\frac{q}{C_1}=\frac{3600}{6}=600 \mathrm{~V}$$
$$\begin{aligned}
& 	herefore V_A-V_P=600 \quad 	herefore 900-V_P=600 \\
& 	herefore V_P=300 V
\end{aligned}$$

Answer

900 V

Answer

100 V

Answer

300 V

Answer

600 V

Electrostatics & Capacitance

In the given figure potential at point 'A' is 900 volt and point 'B' is earthed. What will be the potential at point 'P' ?

Choose the correct answer: