A new LCD high definition TV has a power consumption of 128 watts when operating at 120 volts. How much energy, in kilojoules, would be used in 2.5 hours?
1 Answer
Dec 16, 2017
Explanation:
This question is attempting to confuse us by giving more information than we actually need. We only need the power and time to calculate energy consumption leaving the voltage completely out.
Remember that power is energy per unit time so we can write:
Solving for energy we get:
Of course the units matter so we need to also remember that Watts are Joules per second so we need time in seconds. We can use the conversion factor method to do this:
