1) What is meant by the expression "(I^2)*R losses" in electric circuits?
2) Name and describe two electrical applications where: (a) Joule heating is desirable, (b) Joule heating is undesirable.
3) Given two different resistances, how does the rate of Joule heating in them differ if they are connected to a fixed voltage source: (a) in series? (b) in parallel?
4) A resistor is submerged in an insulated container of water. A voltage of 12 V is applied to the resistor resulting in a current of 1.2 A. If this voltage and current are maintained for 5 minutes, how much electrical energy is dissipated by the resistor?
5) During the 5 minute period described in question 4, the water in the insulated vessel undergoes a temperature increase of 20 °C. Assuming that all of the electrical energy dissipated by the resistor was transferred to the water as heat, what is the mass of the water? (the specific heat of water is 4186 J/kg?°C)