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Assignment 20

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

T0A01 Which of the following is a safety hazard of a 12-volt storage battery?
a.
Touching both terminals with the hands can cause electrical shock
c.
RF emissions from the battery
b.
Shorting the terminals can cause burns, fire, or an explosion
d.
All of these choices are correct
 

 2. 

T0A02 How does current flowing through the body cause a health hazard?
a.
By heating tissue
c.
It causes involuntary muscle contractions
b.
It disrupts the electrical functions of cells
d.
All of these choices are correct
 

 3. 

T0A03 What is connected to the green wire in a three-wire electrical AC plug?
a.
Neutral
c.
Safety ground
b.
Hot
d.
The white wire
 

 4. 


T0A04 What is the purpose of a fuse in an electrical circuit?
a.
To prevent power supply ripple from damaging a circuit
c.
To limit current to prevent shocks
b.
To interrupt power in case of overload
d.
All of these choices are correct
 

 5. 

T0A05 Why is it unwise to install a 20-ampere fuse in the place of a 5-ampere fuse?
a.
The larger fuse would be likely to blow because it is rated for higher current
c.
Excessive current could cause a fire
b.
The power supply ripple would greatly increase
d.
All of these choices are correct
 

 6. 

T0A05 Why is it unwise to install a 20-ampere fuse in the place of a 5-ampere fuse?
a.
The larger fuse would be likely to blow because it is rated for higher current
c.
Excessive current could cause a fire
b.
The power supply ripple would greatly increase
d.
All of these choices are correct
 

 7. 

T0A06 What is a good way to guard against electrical shock at your station?
a.
Use three-wire cords and plugs for all AC powered equipment
c.
Use a circuit protected by a ground-fault interrupter
b.
Connect all AC powered station equipment to a common safety ground
d.
All of these choices are correct
 

 8. 

T0A07 Which of these precautions should be taken when installing devices for lightning protection in a coaxial cable feed line?
a.
Include a parallel bypass switch for each protector so that it can be switched out of the circuit when running high power
c.
Keep the ground wires from each protector separate and connected to station ground
b.
Include a series switch in the ground line of each protector to prevent RF overload from inadvertently damaging the protector
d.
Ground all of the protectors to a common plate which is in turn connected to an external ground
 

 9. 

T0A08 What safety equipment should always be included in home-built equipment that is powered from 120V AC power circuits?
a.
A fuse or circuit breaker in series with the AC hot conductor
c.
An inductor in series with the AC power source
b.
An AC voltmeter across the incoming power source
d.
A capacitor across the AC power source
 

 10. 

T0A09 What kind of hazard is presented by a conventional 12-volt storage battery?
a.
It emits ozone which can be harmful to the atmosphere
c.
Explosive gas can collect if not properly vented
b.
Shock hazard due to high voltage
d.
All of these choices are correct
 

 11. 

T0A10 What can happen if a lead-acid storage battery is charged or discharged too quickly?
a.
The battery could overheat and give off flammable gas or explode
c.
The memory effect will reduce the capacity of the battery
b.
The voltage can become reversed
d.
All of these choices are correct
 

 12. 

T0A11 What kind of hazard might exist in a power supply when it is turned off and disconnected?
a.
Static electricity could damage the grounding system
c.
The fuse might blow if you remove the cover
b.
Circulating currents inside the transformer might cause damage
d.
You might receive an electric shock from the charged stored in large capacitors
 

 13. 

T0B01 When should members of a tower work team wear a hard hat and safety glasses?
a.
At all times except when climbing the tower
c.
At all times when any work is being done on the tower
b.
At all times except when belted firmly to the tower
d.
Only when the tower exceeds 30 feet in height
 

 14. 

T0B02 What is a good precaution to observe before climbing an antenna tower?
a.
Make sure that you wear a grounded wrist strap
c.
Put on a climbing harness and safety glasses
b.
Remove all tower grounding connections
d.
All of the these choices are correct
 

 15. 

T0B03 Under what circumstances is it safe to climb a tower without a helper or observer?
a.
When no electrical work is being performed
c.
When the work being done is not more than 20 feet above the ground
b.
When no mechanical work is being performed
d.
Never
 

 16. 

T0B04 Which of the following is an important safety precaution to observe when putting up an antenna tower?
a.
Wear a ground strap connected to your wrist at all times
c.
Look for and stay clear of any overhead electrical wires
b.
Insulate the base of the tower to avoid lightning strikes
d.
All of these choices are correct
 

 17. 

T0B05 What is the purpose of a gin pole?
a.
To temporarily replace guy wires
c.
To lift tower sections or antennas
b.
To be used in place of a safety harness
d.
To provide a temporary ground
 

 18. 

T0B06 What is the minimum safe distance from a power line to allow when installing an antenna?
a.
Half the width of your property
c.
1/2 wavelength at the operating frequency
b.
The height of the power line above ground
d.
So that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires
 

 19. 

T0B07 Which of the following is an important safety rule to remember when using a crank-up tower?
a.
This type of tower must never be painted
c.
This type of tower must never be climbed unless it is in the fully retracted position
b.
This type of tower must never be grounded
d.
All of these choices are correct
 

 20. 

T0B08 What is considered to be a proper grounding method for a tower?
a.
A single four-foot ground rod, driven into the ground no more than 12 inches from the base
c.
Separate eight-foot long ground rods for each tower leg, bonded to the tower and each other
b.
A ferrite-core RF choke connected between the tower and ground
d.
A connection between the tower base and a cold water pipe
 

 21. 

T0B09 Why should you avoid attaching an antenna to a utility pole?
a.
The antenna will not work properly because of induced voltages
c.
The antenna could contact high-voltage power wires
b.
The utility company will charge you an extra monthly fee
d.
All of these choices are correct
 

 22. 

T0B10 Which of the following is true concerning grounding conductors used for lightning protection?
a.
Only non-insulated wire must be used
c.
Sharp bends must be avoided
b.
Wires must be carefully routed with precise right-angle bends
d.
Common grounds must be avoided
 

 23. 

T0B11 Which of the following establishes grounding requirements for an amateur radio tower or antenna?
a.
FCC Part 97 Rules
c.
FAA tower lighting regulations
b.
Local electrical codes
d.
Underwriters Laboratories' recommended practices
 

 24. 

T0B12 Which of the following is good practice when installing ground wires on a tower for lightning protection?
a.
Put a loop in the ground connection to prevent water damage to the ground system
c.
Ensure that connections are short and direct
b.
Make sure that all bends in the ground wires are clean, right angle bends
d.
All of these choices are correct
 

 25. 

T0C01 What type of radiation are VHF and UHF radio signals?
a.
Gamma radiation
c.
Alpha radiation
b.
Ionizing radiation
d.
Non-ionizing radiation
 

 26. 

T0C02 Which of the following frequencies has the lowest value for Maximum Permissible Exposure limit?
a.
3.5 MHz
c.
440 MHz
b.
50 MHz
d.
1296 MHz
 

 27. 

T0C03 What is the maximum power level that an amateur radio station may use at VHF frequencies before an RF exposure evaluation is required?
a.
1500 watts PEP transmitter output
c.
50 watts PEP at the antenna
b.
1 watt forward power
d.
50 watts PEP reflected power
 

 28. 

T0C04 What factors affect the RF exposure of people near an amateur station antenna?
a.
Frequency and power level of the RF field
c.
Radiation pattern of the antenna
b.
Distance from the antenna to a person
d.
All of these choices are correct
 

 29. 

T0C05 Why do exposure limits vary with frequency?
a.
Lower frequency RF fields have more energy than higher frequency fields
c.
Higher frequency RF fields are transient in nature
b.
Lower frequency RF fields do not penetrate the human body
d.
The human body absorbs more RF energy at some frequencies than at others
 

 30. 

T0C06 Which of the following is an acceptable method to determine that your station complies with FCC RF exposure regulations?
a.
By calculation based on FCC OET Bulletin 65
c.
By measurement of field strength using calibrated equipment
b.
By calculation based on computer modeling
d.
All of these choices are correct
 

 31. 

T0C07 What could happen if a person accidentally touched your antenna while you were transmitting?
a.
Touching the antenna could cause television interference
c.
They might develop radiation poisoning
b.
They might receive a painful RF burn
d.
All of these choices are correct
 

 32. 

T0C08 Which of the following actions might amateur operators take to prevent exposure to RF radiation in excess of FCC-supplied limits?
a.
Relocate antennas
c.
Increase the duty cycle
b.
Relocate the transmitter
d.
All of these choices are correct
 

 33. 

T0C09 How can you make sure your station stays in compliance with RF safety regulations?
a.
By informing the FCC of any changes made in your station
c.
By making sure your antennas have low SWR
b.
By re-evaluating the station whenever an item of equipment is changed
d.
All of these choices are correct
 

 34. 

T0C10 Why is duty cycle one of the factors used to determine safe RF radiation exposure levels?
a.
It affects the average exposure of people to radiation
c.
It takes into account the antenna feed line loss
b.
It affects the peak exposure of people to radiation
d.
It takes into account the thermal effects of the final amplifier
 

 35. 

T0C11 What is the definition of duty cycle during the averaging time for RF exposure?
a.
The difference between the lowest power output and the highest power output of a transmitter
c.
The percentage of time that a transmitter is transmitting
b.
The difference between the PEP and average power output of a transmitter
d.
The percentage of time that a transmitter is not transmitting
 

 36. 

T0C12 How does RF radiation differ from ionizing radiation (radioactivity)?
a.
RF radiation does not have sufficient energy to cause genetic damage
c.
RF radiation is limited in range to a few feet
b.
RF radiation can only be detected with an RF dosimeter
d.
RF radiation is perfectly safe
 

 37. 

T0C13 If the averaging time for exposure is 6 minutes, how much power density is permitted if the signal is present for 3 minutes and absent for 3 minutes rather than being present for the entire 6 minutes?
a.
3 times as much
c.
2 times as much
b.
1/2 as much
d.
There is no adjustment allowed for shorter exposure times
 

 38. 

T2C02 What is one way to recharge a 12-volt lead-acid station battery if the commercial power is out?
a.
Cool the battery in ice for several hours
c.
Connect the battery in parallel with a vehicle’s battery and run the engine
b.
Add acid to the battery
d.
All of these choices are correct
 

 39. 

T4A08 Which type of conductor is best to use for RF grounding?
a.
Round stranded wire
c.
Twisted-pair cable
b.
Round copper-clad steel wire
d.
Flat strap
 

 40. 

T7D12 Which of the following precautions should be taken when measuring high voltages with a voltmeter?
a.
Ensure that the voltmeter has very low impedance
c.
Ensure that the circuit is grounded through the voltmeter
b.
Ensure that the voltmeter and leads are rated for use at the voltages to be measured
d.
Ensure that the voltmeter is set to the correct frequency
 



 
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