Question 32: Electrostats & Capacitance

Question

A capacitor of capacitance $4 \mu \mathrm{~F}$ is charged to a potential of 24 V and then connected in parallel to an uncharged capacitor of capacitance $6 \mu \mathrm{~F}$. The final potential difference across each capacitor will be:

Accepted Answer

First, conserve charge when the two capacitors are connected in parallel (no external losses).
Initial charge on the 4 ÃÂ¼F capacitor:
$$Q_i = C_1V_1 = (4\;\mu	ext F)(24\;	ext V)=96\;\mu	ext C$$
Total capacitance after connection:
$$C_{m tot}=C_1+C_2=4\;\mu	ext F+6\;\mu	ext F=10\;\mu	ext F$$
Final common voltage:
$$V_f=\frac{Q_i}{C_{m tot}}=\frac{96\;\mu	ext C}{10\;\mu	ext F}=9.6\;	ext V$$
Answer: 9.6 V (Option C).

Answer

6.9 V

Answer

8.2 V

Answer

9.6 V

Answer

7.4 V

Electrostats & Capacitance

A capacitor of capacitance 4 \mu \mathrm{~F} is charged to a potential of 24 V and then connected in parallel to an uncharged capacitor of capacitance 6 \mu \mathrm{~F}. The final potential difference across each capacitor will be:

Choose the correct answer: