RF Exposure Safety

What type of radiation are radio signals?

• Gamma radiation

• Ionizing radiation

• Alpha radiation

• Non-ionizing radiation

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NGSS.HS-PS4-3

NGSS.HS-PS4-5

How does RF radiation differ from ionizing radiation (radioactivity)?

• RF radiation does not have sufficient energy to cause chemical changes in cells and damage DNA

• 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

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NGSS.HS-PS4-3

NGSS.HS-PS4-4

Who is responsible for ensuring that no person is exposed to RF energy above the FCC exposure limits?

• The FCC

• The station licensee

• Anyone who is near an antenna

• The local zoning board

At which of the following frequencies does maximum permissible exposure have the lowest value?

• 3.5 MHz

• 50 MHz

• 440 MHz

• 1296 MHz

Tags

NGSS.HS-PS4-4

What factors affect the RF exposure of people near an amateur station antenna?

• Frequency and power level of the RF field

• Distance from the antenna to a person

• Radiation pattern of the antenna

• All these choices are correct

Why do exposure limits vary with frequency?

• 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

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

Tags

NGSS.HS-PS4-4

What hazard is created by touching an antenna during a transmission?

• Electrocution

• RF burn to skin

• Radiation poisoning

• All these choices are correct

Which of the following actions can reduce exposure to RF radiation?

• Relocate antennas

• Relocate the transmitter

• Increase the duty cycle

• All these choices are correct

Tags

NGSS.HS-PS4-5

How does the allowable power density for RF safety change if duty cycle changes from 100 percent to 50 percent?

• It increases by a factor of 3

• It decreases by 50 percent

• It increases by a factor of 2

• There is no adjustment allowed for lower duty cycle

Tags

NGSS.HS-PS4-3

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

• It affects the average exposure to radiation

• It affects the peak exposure to radiation

• It takes into account the antenna feed line loss

• It takes into account the thermal effects of the final amplifier

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-4