Subelement I: Power Sources— Topic 61: Batteries-2
Question 3-61I1
Element 3 (GROL)When an emergency transmitter uses 325 watts and a receiver uses 50 watts, how many hours can a 12.6 volt, 55 ampere-hour battery supply full power to both units?
Explanation
To determine how long the battery can supply power, first calculate the total power consumption of both units. The transmitter uses 325 watts and the receiver uses 50 watts, for a total of 325 W + 50 W = 375 W.
Next, calculate the total current drawn from the battery using the formula Power (P) = Voltage (V) * Current (I). Rearranging for current: I = P / V.
I = 375 W / 12.6 V ≈ 29.76 Amperes.
Finally, calculate the battery's run time by dividing its ampere-hour rating by the total current drawn:
Run Time (hours) = Battery Capacity (Ah) / Current (A)
Run Time = 55 Ah / 29.76 A ≈ 1.848 hours.
Rounding this value gives approximately 1.8 hours, which corresponds to option A. The other options are incorrect as they do not result from these calculations.
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