Subelement E0 Extra class license exam questions

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Group E0A Safety: amateur radio safety practices; RF radiation hazards; hazardous materials; grounding and bonding

E0A01 What is the primary function of an external earth connection or ground rod?

Reduce received noise
Lightning protection
Reduce RF current flow between pieces of equipment
Reduce RFI to telephones and home entertainment systems

E0A02 When evaluating RF exposure levels from your station at a neighbor’s home, what must you do?

Make sure signals from your station are less than the controlled MPE limits
Make sure signals from your station are less than the uncontrolled MPE limits
You need only evaluate exposure levels on your own property
Advise your neighbors of the results of your tests

E0A03 Which of the following would be a practical way to estimate whether the RF fields produced by an amateur radio station are within permissible MPE limits?

Use a calibrated antenna analyzer
Use a hand calculator plus Smith-chart equations to calculate the fields
Use an antenna modeling program to calculate field strength at accessible locations
All of the choices are correct

E0A04 When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?

Only the most powerful transmitter
Only commercial transmitters
Each transmitter that produces 5 percent or more of its MPE limit at accessible locations
Each transmitter operating with a duty-cycle greater than 50 percent

E0A05 What is one of the potential hazards of using microwaves in the amateur radio bands?

Microwaves are ionizing radiation
The high gain antennas commonly used can result in high exposure levels
Microwaves often travel long distances by ionospheric reflection
The extremely high frequency energy can damage the joints of antenna structures

E0A06 Why are there separate electric (E) and magnetic (H) field MPE limits?

The body reacts to electromagnetic radiation from both the E and H fields
Ground reflections and scattering make the field impedance vary with location
E field and H field radiation intensity peaks can occur at different locations
All of these choices are correct

E0A07 How may dangerous levels of carbon monoxide from an emergency generator be detected?

By the odor
Only with a carbon monoxide detector
Any ordinary smoke detector can be used
By the yellowish appearance of the gas

E0A08 What does SAR measure?

Synthetic Aperture Ratio of the human body
Signal Amplification Rating
The rate at which RF energy is absorbed by the body
The rate of RF energy reflected from stationary terrain

E0A09 Which insulating material commonly used as a thermal conductor for some types of electronic devices is extremely toxic if broken or crushed and the particles are accidentally inhaled?

Mica
Zinc oxide
Beryllium Oxide
Uranium Hexafluoride

E0A10 What toxic material may be present in some electronic components such as high voltage capacitors and transformers?

Polychlorinated Biphenyls
Polyethylene
Polytetrafluroethylene
Polymorphic silicon

E0A11 Which of the following injuries can result from using high-power UHF or microwave transmitters?

Hearing loss caused by high voltage corona discharge
Blood clotting from the intense magnetic field
Localized heating of the body from RF exposure in excess of the MPE limits
Ingestion of ozone gas from the cooling system

Extra Class License Exam Questions

Subelement E0

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