A laboratory power supply is programmed to deliver the following square-wave voltage across a fixed 20 Ω resistor:
• 60 V for the first 5.0 s
• 30 V for the next 10.0 s
• 0 V for the final 5.0 s
Assume transition times between levels are negligible and the resistance remains constant.
(a) Create a quantitative table that lists, for each of the three time intervals, the current through the resistor and the instantaneous rate at which electrical energy is converted within the resistor.
(b) Determine the total electrical energy converted into thermal energy during the entire 20 s program.
(c) Calculate the average power delivered to the resistor over the 20 s interval.
(d) Using your results, discuss whether operating the resistor under the given voltage program would raise its temperature more, less, or the same amount as operating it at a steady 40 V for 20 s. Support your claim with quantitative evidence.