If a marine radiotelephone receiver uses 75 watts and a transmitter uses 325 watts, how long can they both operate before discharging a 50 ampere-hour, 12-volt battery?

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Multiple Choice

If a marine radiotelephone receiver uses 75 watts and a transmitter uses 325 watts, how long can they both operate before discharging a 50 ampere-hour, 12-volt battery?

The main idea is to find how long a 50 Ah, 12 V battery can run two devices that together draw a certain amount of power. First add the power usage: 75 watts for the receiver plus 325 watts for the transmitter equals 400 watts total. To find the current drawn from the 12-volt battery, divide the total power by the battery voltage: 400 W / 12 V = about 33.3 A. The battery capacity is 50 ampere-hours, so the runtime under a constant current draw is 50 Ah / 33.3 A ≈ 1.5 hours, which is 1 hour and 30 minutes. So, under ideal conditions, they can operate for 1 1/2 hours.

The main idea is to find how long a 50 Ah, 12 V battery can run two devices that together draw a certain amount of power.

First add the power usage: 75 watts for the receiver plus 325 watts for the transmitter equals 400 watts total. To find the current drawn from the 12-volt battery, divide the total power by the battery voltage: 400 W / 12 V = about 33.3 A.

The battery capacity is 50 ampere-hours, so the runtime under a constant current draw is 50 Ah / 33.3 A ≈ 1.5 hours, which is 1 hour and 30 minutes.

So, under ideal conditions, they can operate for 1 1/2 hours.

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