All 18 FCC GROL questions for 3I Power Sources with the correct answers marked, from the official current FCC question pool. Test yourself with the free practice exam.
3-60I1
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. ✓
3-60I2
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.
3-60I3
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.
3-60I4
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.
3-60I5
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. ✓
3-60I6
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.
3-61I1
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.
3-61I2
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.
3-61I3
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.
3-61I4
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.
3-61I5
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.
3-61I6
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. ✓
3-62I1
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. ✓
3-62I2
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.
3-62I3
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
3-62I4
What is the line current of a 7 horsepower motor operating on 120 volts at full load, a power factor of 0.8, and 95% efficient?
A. 4.72 amps.
B. 13.03 amps.
C. 56 amps.
D. 57.2 amps. ✓
3-62I5
A 3 horsepower, 100 V DC motor is 85% efficient when developing its rated output. What is the current?
A. 8.545 amps.
B. 20.345 amps.
C. 26.300 amps. ✓
D. 25.000 amps.
3-62I6
The output of a separately-excited AC generator running at a constant speed can be controlled by:
A. The armature.
B. The amount of field current. ✓
C. The brushes.
D. The exciter.