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Technician Class Exam Question Pool

effective 7/01/2014 thru 6/30/2018

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Topic T0: Safety


T0A-2014: Power circuits and hazards: hazardous voltages; fuses and circuit breakers; grounding; lightning protection; battery safety; electrical code compliance

T0A01-2014: Which of the following is a safety hazard of a 12-volt storage battery?

Shorting the terminals can cause burns, fire, or an explosion

Touching both terminals with the hands can cause electrical shock

RF emissions from the battery

All of these choices are correct



T0A02-2014: How does current flowing through the body cause a health hazard?

All of these choices are correct

By heating tissue

It disrupts the electrical functions of cells

It causes involuntary muscle contractions



T0A03-2014: What is connected to the green wire in a three-wire electrical AC plug?

Safety ground

Neutral

Hot

The white wire



T0A04-2014: What is the purpose of a fuse in an electrical circuit?

To interrupt power in case of overload

To prevent power supply ripple from damaging a circuit

To limit current to prevent shocks

All of these choices are correct



T0A05-2014: Why is it unwise to install a 20-ampere fuse in the place of a 5-ampere fuse?

Excessive current could cause a fire

The larger fuse would be likely to blow because it is rated for higher current

The power supply ripple would greatly increase

All of these choices are correct



T0A06-2014: What is a good way to guard against electrical shock at your station?

All of these choices are correct

Use three-wire cords and plugs for all AC powered equipment

Connect all AC powered station equipment to a common safety ground

Use a circuit protected by a ground-fault interrupter



T0A07-2014: Which of these precautions should be taken when installing devices for lightning protection in a coaxial cable feed line?

Ground all of the protectors to a common plate which is in turn connected to an external ground

Include a parallel bypass switch for each protector so that it can be switched out of the circuit when running high power

Include a series switch in the ground line of each protector to prevent RF overload from inadvertently damaging the protector

Keep the ground wires from each protector separate and connected to station ground



T0A08-2014: What safety equipment should always be included in home-built equipment that is powered from 120V AC power circuits?

A fuse or circuit breaker in series with the AC hot conductor

An AC voltmeter across the incoming power source

An inductor in series with the AC power source

A capacitor across the AC power source



T0A09-2014: What kind of hazard is presented by a conventional 12-volt storage battery?

Explosive gas can collect if not properly vented

It emits ozone which can be harmful to the atmosphere

Shock hazard due to high voltage

All of these choices are correct



T0A10-2014: What can happen if a lead-acid storage battery is charged or discharged too quickly?

The battery could overheat and give off flammable gas or explode

The voltage can become reversed

The memory effect will reduce the capacity of the battery

All of these choices are correct



T0A11-2014: What kind of hazard might exist in a power supply when it is turned off and disconnected?

You might receive an electric shock from the charged stored in large capacitors

Static electricity could damage the grounding system

Circulating currents inside the transformer might cause damage

The fuse might blow if you remove the cover






T0B-2014: Antenna safety: tower safety; erecting an antenna support; overhead power lines; installing an antenna

T0B01-2014: When should members of a tower work team wear a hard hat and safety glasses?

At all times when any work is being done on the tower

At all times except when climbing the tower

At all times except when belted firmly to the tower

Only when the tower exceeds 30 feet in height



T0B02-2014: What is a good precaution to observe before climbing an antenna tower?

Put on a climbing harness and safety glasses

Make sure that you wear a grounded wrist strap

Remove all tower grounding connections

All of the these choices are correct



T0B03-2014: Under what circumstances is it safe to climb a tower without a helper or observer?

Never

When no electrical work is being performed

When no mechanical work is being performed

When the work being done is not more than 20 feet above the ground



T0B04-2014: Which of the following is an important safety precaution to observe when putting up an antenna tower?

Look for and stay clear of any overhead electrical wires

Wear a ground strap connected to your wrist at all times

Insulate the base of the tower to avoid lightning strikes

All of these choices are correct



T0B05-2014: What is the purpose of a gin pole?

To lift tower sections or antennas

To temporarily replace guy wires

To be used in place of a safety harness

To provide a temporary ground



T0B06-2014: What is the minimum safe distance from a power line to allow when installing an antenna?

So that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires

Half the width of your property

The height of the power line above ground

1/2 wavelength at the operating frequency



T0B07-2014: Which of the following is an important safety rule to remember when using a crank-up tower?

This type of tower must never be climbed unless it is in the fully retracted position

This type of tower must never be painted

This type of tower must never be grounded

All of these choices are correct



T0B08-2014: What is considered to be a proper grounding method for a tower?

Separate eight-foot long ground rods for each tower leg, bonded to the tower and each other

A single four-foot ground rod, driven into the ground no more than 12 inches from the base

A ferrite-core RF choke connected between the tower and ground

A connection between the tower base and a cold water pipe



T0B09-2014: Why should you avoid attaching an antenna to a utility pole?

The antenna could contact high-voltage power wires

The antenna will not work properly because of induced voltages

The utility company will charge you an extra monthly fee

All of these choices are correct



T0B10-2014: Which of the following is true concerning grounding conductors used for lightning protection?

Sharp bends must be avoided

Only non-insulated wire must be used

Wires must be carefully routed with precise right-angle bends

Common grounds must be avoided



T0B11-2014: Which of the following establishes grounding requirements for an amateur radio tower or antenna?

Local electrical codes

FCC Part 97 Rules

FAA tower lighting regulations

Underwriters Laboratories' recommended practices



T0B12-2014: Which of the following is good practice when installing ground wires on a tower for lightning protection?

Ensure that connections are short and direct

Put a loop in the ground connection to prevent water damage to the ground system

Make sure that all bends in the ground wires are clean, right angle bends

All of these choices are correct






T0C-2014: RF hazards: radiation exposure; proximity to antennas; recognized safe power levels; exposure to others; radiation types; duty cycle

T0C01-2014: What type of radiation are VHF and UHF radio signals?

Non-ionizing radiation

Gamma radiation

Ionizing radiation

Alpha radiation



T0C02-2014: Which of the following frequencies has the lowest value for Maximum Permissible Exposure limit?

50 MHz

3.5 MHz

440 MHz

1296 MHz



T0C03-2014: What is the maximum power level that an amateur radio station may use at VHF frequencies before an RF exposure evaluation is required?

50 watts PEP at the antenna

1500 watts PEP transmitter output

1 watt forward power

50 watts PEP reflected power



T0C04-2014: What factors affect the RF exposure of people near an amateur station antenna?

All of these choices are correct

Frequency and power level of the RF field

Distance from the antenna to a person

Radiation pattern of the antenna



T0C05-2014: Why do exposure limits vary with frequency?

The human body absorbs more RF energy at some frequencies than at others

Lower frequency RF fields have more energy than higher frequency fields

Lower frequency RF fields do not penetrate the human body

Higher frequency RF fields are transient in nature



T0C06-2014: Which of the following is an acceptable method to determine that your station complies with FCC RF exposure regulations?

All of these choices are correct

By calculation based on FCC OET Bulletin 65

By calculation based on computer modeling

By measurement of field strength using calibrated equipment



T0C07-2014: What could happen if a person accidentally touched your antenna while you were transmitting?

They might receive a painful RF burn

Touching the antenna could cause television interference

They might develop radiation poisoning

All of these choices are correct



T0C08-2014: Which of the following actions might amateur operators take to prevent exposure to RF radiation in excess of FCC-supplied limits?

Relocate antennas

Relocate the transmitter

Increase the duty cycle

All of these choices are correct



T0C09-2014: How can you make sure your station stays in compliance with RF safety regulations?

By re-evaluating the station whenever an item of equipment is changed

By informing the FCC of any changes made in your station

By making sure your antennas have low SWR

All of these choices are correct



T0C10-2014: Why is duty cycle one of the factors used to determine safe RF radiation exposure levels?

It affects the average exposure of people to radiation

It affects the peak exposure of people to radiation

It takes into account the antenna feed line loss

It takes into account the thermal effects of the final amplifier



T0C11-2014: What is the definition of duty cycle during the averaging time for RF exposure?

The percentage of time that a transmitter is transmitting

The difference between the lowest power output and the highest power output of a transmitter

The difference between the PEP and average power output of a transmitter

The percentage of time that a transmitter is not transmitting



T0C12-2014: How does RF radiation differ from ionizing radiation (radioactivity)?

RF radiation does not have sufficient energy to cause genetic damage

RF radiation can only be detected with an RF dosimeter

RF radiation is limited in range to a few feet

RF radiation is perfectly safe



T0C13-2014: 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?

2 times as much

3 times as much

1/2 as much

There is no adjustment allowed for shorter exposure times





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