Question

A) Your microwave oven is 64% efficient. How much electrical energy must it use to produce 900 J of radiant energy? Show all your work.

Answer 1

$$\eta=\frac{W}{E_{tot}}$$

$$0.64=\frac{\rm 900\: J}{E_{tot}}$$

$$E_{tot}=\rm\frac{900\: J}{0.64}=1406\: J$$