A capacitor of capacitance 8.4 pF8.4\text{ pF}8.4 pF consists of two parallel metal plates separated by an insulator of thickness 1.5 mm1.5\text{ mm}1.5 mm. The area of overlap between the plates is 5.0×10−4 m25.0 \times 10^{-4}\text{ m}^25.0×10−4 m2. Calculate the permittivity of the insulator between the capacitor plates.
permittivity = ................................... F m−1\text{F m}^{-1}F m−1
Fig. 21 shows a circuit.
Fig. 21
The capacitance of each capacitor is 800 μF800\ \mu\text{F}800 μF. The resistance of the resistor is 15 kΩ15\text{ k}\Omega15 kΩ. The cell has e.m.f. 3.0 V3.0\text{ V}3.0 V and negligible internal resistance.
Calculate the total capacitance CCC in the circuit.
CCC = ................................... μF\mu\text{F}μF
The switch S is closed at time t=0t = 0t=0. There is zero potential difference across the capacitors at t=0t = 0t=0. Calculate the potential difference VVV across the resistor at time t=9.0 st = 9.0\text{ s}t=9.0 s.
VVV = ................................... V\text{V}V
