Answer:
12580J.
Explanation:
Given the following parameters;
Current, I=850mAh
Time, t=2s
Voltage, V=7.4 V
Energy = Power * Time
Where; Power = Current(I) * Voltage(v)
E = I*V*T
Since, we were given current in ampere-hour, we would use;
Energy(J) = Charge(C) * Voltage(V)
Charge(C) = Current (I) * Time(t)
C = 850*2=1700 coulombs of charge.
Therefore, Energy(J) = Charge(C) * Voltage(V)
Energy = 1700 * 7.4
Energy = 12580J
Hence, the overall energy capacity of the battery is 12580Joules.