Using the formula for energy calculation, if a device uses 200 watts for 5 hours, how much energy is consumed?

To determine the energy consumed by a device using a specified amount of power over a given time, the formula to use is:

Energy (in kilowatt-hours, kWh) = Power (in kilowatts, kW) × Time (in hours, h)

In this case, the device uses 200 watts. First, we need to convert this power into kilowatts:

200 watts = 0.2 kilowatts (since 1000 watts = 1 kilowatt).

Next, the time of operation is given as 5 hours. Now we can substitute the values into the formula:

Energy = 0.2 kW × 5 h = 1 kWh.

Thus, the total energy consumed by the device is 1 kWh. This shows that the calculation was performed accurately in arriving at the energy use.

Since 1 kWh is the correct total energy consumption, it aligns perfectly with the first option. The value provided as the answer (2 kWh) does not correspond with the computed result of 1 kWh; therefore, revisiting the calculations confirms the accuracy in the approach.