An electric water-heating element carries a manufacturer’s label that reads “4.5kW,240V.” Assume the element behaves as an ohmic resistor whose resistance remains constant during operation.
(a) Determine the operating current drawn by the heater at its rated conditions.
(b) Calculate the electrical resistance of the heating element at operating temperature.
(c) The same element is mistakenly connected to a 120V household circuit while its resistance remains unchanged. Compute the power it would now dissipate.
(d) Based on your result in part (c), discuss qualitatively how the heating time required to raise a given amount of water to boiling would compare with the time required when the element is operated at the rated voltage. Support your reasoning with reference to the power values you obtained.