Final answer:
The correct answer to which NEC section states installation requirements for equipment not associated with hydro massage tubs is a. 680.72, chapters 1 through 4.
Step-by-step explanation:
The question pertains to the National Electrical Code (NEC), specifically asking which section states that luminaires, switches, receptacles, and other electrical equipment not associated with the hydro massage tub should be installed according to certain NEC chapters. The correct answer is a. 680.72, chapters 1 through 4. These chapters of the NEC cover general installation requirements for electrical equipment to ensure safety and functionality.
In constructing a problem involving the resistance of each filament to obtain a certain intensity of light on the bathroom floor from a 250-W heat lamp, one would need to consider electrical power (P), voltage (V), and resistance (R), using the formula P = V^2/R to find the resistance when the voltage is known and the power of each lamp is given. Additionally, the impact of any concave mirrors behind the filaments in directing the light intensity would have to be factored in, according to the principles of optics and geometry.