(1)In a series circuit, the current through each of the components is the same, and the voltage across the circuit is the sum of the voltages across each component. In aparallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component.
(2) Conductors are the substances which allow the electricity to pass through them while insulators resist electricity. A conductor is something which allows electric current to flow through it freely whereas an insulator prevents any electric current flowing through it.
The resistance of an object (i.e., a resistor) depends on its shape and the material of which it is composed. Resistivity ρ is an intrinsic property of a material and directly proportional to the total resistance R, an extrinsic quantity that depends on the length and cross-sectional area of a resistor.
(4)A short circuit is an electric circuit offering little or no resistance to the flow of electrons. Short circuits are dangerous with high voltage power sources because thehigh currents encountered can cause large amounts of heat energy to be released.