What is the output of a residential electric furnace when the voltage impressed is equal to 235 V and its current draw is 40 A?

To find the output of a residential electric furnace, you can use the formula for calculating the power in watts, which is derived from the voltage and current. This is given by the equation:

Power (watts) = Voltage (volts) × Current (amperes)

In this scenario, the voltage is 235 V and the current draw is 40 A.

Calculating the power:

Power = 235 V × 40 A = 9,400 watts.

Next, to convert watts to British thermal units per hour (Btuh), you can use the conversion factor where 1 watt is approximately equal to 3.412 Btuh. Therefore, you would multiply the power in watts by this conversion factor:

Output (Btuh) = 9,400 watts × 3.412 Btuh/watt = 32,080 Btuh.

This results in an output of 32,080 Btuh for the residential electric furnace when it operates at 235 V and draws 40 A. Thus, the choice reflecting this calculated output correctly is indeed the second option, which indicates a thorough application of electrical and conversion principles.