Answer:
1.42 KJ
Explanation:
solution:
power in beginning [tex]p_{0}[/tex]=(1.5 V).(9×[tex]10^{-3}[/tex] A)
                  = 13.5 mW
after continuous 37 hours it drops to
                  [tex]p_{37}[/tex]=(1 V).(9×[tex]10^{-3}[/tex] A)
                     =9 mW
When the voltage will drop energy will not remain the same but the voltage drop will always remain same if the voltage was drop to for example from 5 V to 4.5 V the drop will remain the same.
         37 hours= 37.60.60
                 =133200‬ s
               w=(9×[tex]10^{-3}[/tex] A×133200‬ )+[tex]\frac{1}{2}(13.5.10^{-3}-9.10^{-3})(133200)[/tex]
                 =1.42 KJ
NOTE:
There maybe a calculation error but the method is correct.