Q4. Assertion: the equivalent capacitance of capacitors in series is less than the smallest of them. Reason: in series the reciprocals of the capacitances add. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion: 1/C is the sum of all the 1/Ci, so it is larger than any single 1/Ci, and C is smaller than every Ci (NCERT Eq. (2.60), page 72).
Q5. A 3.0 µF and a 6.0 µF capacitor are joined in series, and the pair is joined in parallel with a 4.0 µF capacitor. Find the equivalent capacitance.
The series pair gives (3.0 × 6.0)/(3.0 + 6.0) = 2.0 µF. In parallel with 4.0 µF: C = 2.0 + 4.0 = 6.0 µF (NCERT Eqs. (2.58) and (2.64), page 72).
Q6. Four identical capacitors, each of capacitance C0, are joined first all in series and then all in parallel. Find the ratio of the parallel to the series capacitance.
Series: C0/4. Parallel: 4C0. The ratio is 4C0 ÷ (C0/4) = 16 (NCERT Eqs. (2.60) and (2.67), page 72).