Acell phone phone charger used 4.83 joules per second when plugged into an outlet, but 1,31 joules per second actually goes into the cell phone battery. the remaining joules are lost as heat. that's why the battery feels warm after it has been charging for a while. how efficient is the charger?

The magnitude of the amount of energy released by burning a fuel source, measured in energy per unit mass, is called its fuel value. note that the fuel value is the negative of the isobaric specific heat of combustion for the fuel. if all the energy obtained from burning 1.23 pounds of butane with a fuel value of 10.85 kcal/g is used to heat 128.0 kg of water at an initial temperature of 18.3 °c, what is the final temperature? note that 1 lb = 453.6 g.