Answer:
Part A:
In W-h:
Energy Stored=1440 W-h
In Joules:
[tex]Energy Stored=5.184*10^6Joules\\Energy Stored=5.184 MJ[/tex]
Part B:
In W-h:
Energy left=240 W-h
In Joules:
Energy left= 8.64*10^5 J
Explanation:
Part A:
We are given rating 120A-h and voltage 12 V
Energy Stored= Rating*Voltage (Gives us units W-h)
Energy Stored=120A-h*12V
Energy Stored=1440 W-h
Converting it into joules (watt=joules/sec)
Energy Stored=[tex]1440 Joules * \frac{3600sec}{h}h[/tex]
Energy Stored=5184000 Joules
[tex]Energy Stored=5.184*10^6Joules\\Energy Stored=5.184 MJ[/tex]
Part B:
Energy used by lights for 8h=150*8
Energy used by lights for 8h=1200W-h
Energy left= Energy Stored(Calculated above)- Energy used by lights for 8h
Energy left=1440-1200
Energy left=240 W-h
Energy left=[tex]240 Joules * \frac{3600sec}{h}h[/tex]
Energy left=864000 Joules
Energy left= 8.64*10^5 J
