Final answer:
The BTU output of a 10 kW heater is 34,120 BTU/hr, which is obtained by multiplying 10 kW by the conversion factor of 3,412 BTU/kW.
Step-by-step explanation:
To find the BTU (British Thermal Units) output of a 10 kW (kilowatts) heater, we need to convert the power rating from kilowatts to BTUs per hour. The conversion factor stated is 1 kilowatt (kW) equals 3,412 BTUs per hour. Therefore, to convert 10 kW to BTUs:
10 kW × 3,412 BTU/kW = 34,120 BTU/hr.
Hence, the correct BTU output of a 10 kW heater is 34,120 BTU, which corresponds to the option D.