Which of the following is a safety hazard of a 12-volt storage battery that lacks internal protection circuitry?
BShorting the terminals can cause burns, fire, or an explosion
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Subelement T0 question review
All 36 official questions with the exact winning phrase marked.
What health hazard is posed by electrical current flowing through the body?
DAll these choices are correct
In the United States, what circuit does black wire insulation indicate in a three-wire 120 V AC cable?
BHot
What is the purpose of a fuse in an electrical circuit?
BTo remove power in case of an overload
Why should a 5-ampere fuse never be replaced with a 20-ampere fuse?
CExcessive current could cause a fire
What is a good way to guard against electrical shock at your station?
DAll these choices are correct
Where should a lightning arrester be installed in a coaxial feed line?
DOn a grounded panel near where feed lines enter the building
Where should a fuse or circuit breaker be installed in a 120V AC power circuit?
AIn series with the hot conductor only
What should be done to all external ground rods or earth connections?
CBond them together with heavy wire or conductive strap
What hazard exists when rapidly charging or discharging an unprotected battery?
AOverheating or out-gassing
What hazard exists in a power supply immediately after turning it off?
DCharge stored in filter capacitors
Which of the following precautions should be taken when measuring high voltages with a voltmeter?
BEnsure that the voltmeter and its leads are rated for use at the voltages being measured
Which of the following is good practice when installing ground wires on a tower for lightning protection?
CEnsure that connections are short and direct
What is required when climbing an antenna tower?
DAll these choices are correct
Under what circumstances is it safe to climb a tower without a helper or observer?
DNever
Which of the following is an important safety precaution to observe when putting up an antenna tower?
CLook for and stay clear of any overhead electrical wires
What is the purpose of a safety wire through a turnbuckle used to tension guy lines?
BPrevent loosening of the turnbuckle from vibration
What is the minimum safe distance from a power line to allow when installing an antenna?
DEnough so that if the antenna falls, no part of it can come within 10 feet of the power wires
Which of the following is an important safety rule to remember when using a crank-up tower?
CThis type of tower must not be climbed unless it is retracted, or mechanical safety locking devices have been installed
Which is a proper grounding method for a tower?
DSeparate eight-foot ground rods for each tower leg, bonded to the tower and each other
Why should you avoid attaching an antenna to a utility pole?
CThe antenna could contact high-voltage power lines
Which of the following is true when installing grounding conductors used for lightning protection?
CSharp bends must be avoided
Which of the following establishes grounding requirements for an amateur radio tower or antenna?
BLocal electrical codes
What type of radiation are radio signals?
DNon-ionizing radiation
Which of the following bands has the lowest maximum permissible exposure for RF safety?
B50 MHz
How does the allowable power density for RF safety change if duty cycle changes from 100 percent to 50 percent?
CIt increases by a factor of 2
What factors affect the RF exposure of people near an amateur station antenna?
DAll these choices are correct
Why do exposure limits vary with frequency?
DThe human body absorbs more RF energy at some frequencies than at others
Which of the following is an acceptable method to determine whether your station complies with FCC RF exposure regulations?
DAll these choices are correct
What hazard is created by touching an antenna during a transmission?
BRF burn to skin
Which of the following actions can reduce exposure to RF radiation?
ARelocate antennas
How can you make sure your station stays in compliance with RF safety regulations?
BBy re-evaluating the station whenever an item in the transmitter or antenna system is changed
Why is duty cycle one of the factors used to determine safe RF radiation exposure levels?
AIt affects the average exposure to radiation
What is the definition of duty cycle during the averaging time for RF exposure?
CThe percentage of time that a transmitter is transmitting
How does RF radiation differ from ionizing radiation (radioactivity)?
ARF radiation does not have sufficient energy to cause chemical changes in cells and damage DNA
Who is responsible for ensuring that no person is exposed to RF energy above the FCC exposure limits?
BThe station licensee