Understanding what makes a good conductor or insulator.

What property makes a given material a good conductor? What property makes a given material a good insulator?

Circuit involving resistances; determination of unknown resistance and the voltages at the terminal points.

Determine the voltage drop across each of the resistors given in the network (See figure). Also determine the unknown resistance R.

capacitance

A cardiac defibrilator is used to shock a heart that is beating erratically. A capacitor in this device is charged to 6150 V and stores 218J of energy. What is its capacitance?

DC circuits

Three 25 ohms lightbulbs and three 100.0 ohms lightbulbs are connected in series. what is the total resistance of the circuit? What is their resistance if all six are wired in parallel?

DC circuits

You have three capacitors, of capacitance 1610pF, 7240pF and 0.0270 micro F. what is the maximum capacitance that you can form from these? what is the minimum capacitance that you can form from these?