A capacitor of capacitance 12.5 pF12.5\text{ pF}12.5 pF consists of two parallel metal plates separated by an insulator of thickness 0.80 mm0.80\text{ mm}0.80 mm. The area of overlap between the plates is 3.2×10−4 m23.2 \times 10^{-4}\text{ m}^23.2×10−4 m2. Calculate the permittivity of the insulator between the capacitor plates.
permittivity = ................................... F m−1\text{F m}^{-1}F m−1
Fig. 1 shows a circuit containing a cell, a switch, a resistor, and a network of three identical capacitors.
Fig. 1
The capacitance of each capacitor is 450 μF450\ \mu\text{F}450 μF. The resistance of the resistor is 12 kΩ12\text{ k}\Omega12 kΩ. The cell has e.m.f. 6.0 V6.0\text{ V}6.0 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=5.4 st = 5.4\text{ s}t=5.4 s.
VVV = ................................... V\text{V}V
