SUB-ELEMENT I Flashcards
When a lead-acid storage battery is being charged, a harmful effect to humans is:
A. Internal plate sulfation may occur under constant charging.
B. Emission of oxygen.
C. Emission of chlorine gas.
D. Emission of hydrogen gas.
D
A battery with a terminal voltage of 12.5 volts is to be trickle-charged at a 0.5 A rate. What resistance should be connected in series with the battery to charge it from a 110-V DC line?
A. 95 ohms.
B. 300 ohms.
C. 195 ohms.
D. None of these.
C
What capacity in amperes does a storage battery need to be in order to operate a 50 watt transmitter for 6 hours? Assume a continuous transmitter load of 70% of the key-locked demand of 40 A, and an emergency light load of 1.5 A.
A. 100 ampere-hours.
B. 177 ampere-hours.
C. 249 ampere-hours.
D. None of these.
B
What is the total voltage when 12 Nickel-Cadmium batteries are connected in series?
A. 12 volts.
B. 12.6 volts.
C. 15 volts.
D. 72 volts.
C
The average fully-charged voltage of a lead-acid storage cell is:
A. 1 volt.
B. 1.2 volts.
C. 1.56 volts.
D. 2.06 volts.
D
A nickel-cadmium cell has an operating voltage of about:
A. 1.25 volts.
B. 1.4 volts.
C. 1.5 volts.
D. 2.1 volts.
A
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?
A. 1.8 hours.
B. 6 hours.
C. 3 hours.
D. 1.2 hours.
A
What current will flow in a 6 volt storage battery with an internal resistance of 0.01 ohms, when a 3-watt, 6-volt lamp is connected?
A. 0.4885 amps.
B. 0.4995 amps.
C. 0.5566 amps.
D. 0.5795 amps.
B
A ship RADAR unit uses 315 watts and a radio uses 50 watts. If the equipment is connected to a 50 ampere-hour battery rated at 12.6 volts, how long will the battery last?
A. 1 hour 43 minutes.
B. 28.97 hours.
C. 29 minutes.
D. 10 hours, 50 minutes.
A
If a marine radiotelephone receiver uses 75 watts of power and a transmitter uses 325 watts, how long can they both operate before discharging a 50 ampere-hour 12 volt battery?
A. 40 minutes.
B. 1 hour.
C. 1 1/2 hours.
D. 6 hours.
C
A 6 volt battery with 1.2 ohms internal resistance is connected across two light bulbs in parallel whose resistance is 12 ohms each. What is the current flow?
A. 0.57 amps.
B. 0.83 amps.
C. 1.0 amps.
D. 6.0 amps.
B
A 12.6 volt, 8 ampere-hour battery is supplying power to a receiver that uses 50 watts and a RADAR system that uses 300 watts. How long will the battery last?
A. 100.8 hours.
B. 27.7 hours.
C. 1 hour.
D. 17 minutes or 0.3 hours.
D
What occurs if the load is removed from an operating series DC motor?
A. It will stop running.
B. Speed will increase slightly.
C. No change occurs.
D. It will accelerate until it falls apart.
D
If a shunt motor running with a load has its shunt field opened, how would this affect the speed of the motor?
A. It will slow down.
B. It will stop suddenly.
C. It will speed up.
D. It will be unaffected.
C
The expression “voltage regulation” as it applies to a shunt-wound DC generator operating at a constant frequency refers to:
A. Voltage fluctuations from load to no-load.
B. Voltage output efficiency.
C. Voltage in the secondary compared to the primary.
D. Rotor winding voltage ratio
A
