A battery charger is connected to a dead battery and delivers a current of 4.5 A for 6.0 hours, keeping the voltage across the battery terminals at 12 V in the process. How much energy is delivered to the battery?

Answer 1

Power(W) x Time (s) = Energy (Joules)

The power in watts is (Volts)x(Amperes)

Now do the numbers.

If these equations are not familiar to you by now, you are not learning much physics.