1. (D): Similarly to resistors, capacitors can be placed in series or parallel. But because of the differences in their electrical properties, their formulae are reversed. The total capacitance of capacitors in parallel (mounted by Y-jumper) is equal to the sum of all the individual capacitances. The total capacitance of capacitors placed in series is the inverse of the reciprocal of the sum of individual capacitances. (Misulis and Head 2003, pp. 30-31)

2. (C): The threshold current for induction of ventricular fibrillation is approximately 100 mA. Because this current spreads out as it passes through the body, only a small fraction will pass through the heart. Consequently, if applied directly to the heart, 0.1 mA may be enough to induce ventricular fibrillation. (Ebersole and Pedley 2003, pp. 66-67; Daube 2002, p. 19)

3. (B): Kirchhoff’s laws define the principle of conservation of energy. Kirchhoff’s current law states that at any point in an electrical circuit where charge density is not changing in time, the sum of currents flowing toward that point is equal to the sum of currents flowing away from that point.

Kirchhoff’s voltage law states that the directed sum of the electrical potential differences around any closed circuit must be zero. (Daube 2002, p. 5; Misulis and Head 2003, pp. 27-28)

4. (D): A capacitor is a device that stores electric charge. It consists of two charged conductors separated by an insulator (dielectric) such that no charge can pass through but charges segregate on both of its sides. After it is fully charged, it will act as battery when the current source is shut down. Its charge q is proportional to the potential difference V (q = CV) where C is the capacitance measured in coulombs per volt or Farad (F). (Ebersole and Pedley 2003, pp. 35-36; Misulis and Head 2003, p. 19)

5. (D): An inductor or electromagnet consists of coils of wire that generates a magnetic field when traversed by a current. An inductor has the property of resisting any change in current flow by producing an electromagnetic field. It has a property called inductance and is measured in seconds per ampere or Henry (H). Inductance has the same relationship to current that capacitance has to voltage. (Daube 2002, p. 5)

6. (C): Electric shock results from current flow through the body. It requires two connections to the body—an entry point, which is the apparatus and an exit point, which is the ground. It also requires a low resistance pathway. (Daube 2002, pp. 17-18)

7. (D): Higher risk of electrocution occurs in susceptible patients. Premorbid heart conditions, pacemakers, and invasive instrumentation are all risk factors for ventricular fibrillation. In these patients the maximal allowed leakage current is 10 to 20 µA. (Ebersole and Pedley 2003, pp. 65-66; Daube 2002, p. 25)