Forms of Radiation Practice Test

Review the following concepts if needed:

• EM Fields Help
• ELF Fields Help
• Rf Waves Help
• Beyond the Radio Spectrum Help
• Radioactivity Help

Forms of Radiation Practice Test

A good score is eight correct. Answers are given at the end.

1. A radio transmitter is said to operate in the 15-m band. What is the frequency corresponding to a wavelength of 15 m?

(a) 20 Hz

(b) 20 kHz

(c) 20 MHz

(d) 20 GHz

2. A thick lead barrier is almost perfectly transparent to

(a) UV radiation.

(b) beta particles.

(c) alpha particles.

(d) neutrinos.

3. The most energetic EM fields (in terms of the energy in each photon) take the form of

(a) alpha particles.

(b) ELF radiation.

(c) rf.

(d) gamma rays.

4. In order for an EM field to be produced, charge carriers must be

(a) in motion.

(b) accelerating.

(c) perpendicular to electrical lines of flux.

(d) perpendicular to magnetic lines of flux.

5. A certain radioactive sample loses exactly seven-eighths of its radiation intensity after 240 years. What is the half-life of this material?

(a) 30 years

(b) 80 years

(c) 160 years

(d) 210 years

6. Medium-frequency radio waves originating in space cannot reach the Earth’s surface because

(a) the EM noise from the Sun drowns them out.

(b) the solar wind deflects them from the Earth.

(c) the Sun’s magnetic field traps them in solar orbit.

(d) they cannot penetrate the Earth’s ionosphere.

7. When radio waves travel long distances because they are trapped between layers of air having different temperatures, the effect is known as

(a) ground wave.

(b) surface wave.

(c) ducting.

(d) sporadic-E.

8. Greenhouse effect in the Earth’s environment takes place because

(a) the atmosphere is transparent to IR at some wavelengths and opaque to IR at other wavelengths.

(b) the atmosphere does not contain enough oxygen to block IR from the Sun.

(c) the ozone hole is growing, letting in more and more IR.

(d) the polar ice caps are melting.

9. A major advantage of a hydrogen fusion reactor over a fission reactor is the fact that

(a) a hydrogen fusion reactor is cooler than a fission reactor.

(b) a hydrogen fusion reactor is easier to build than a fission reactor.

(c) a fusion reactor produces no radioactive waste.

(d) a fusion reactor can be used as a bomb in case of emergency.

10. A good way to protect yourself against ELF

(a) is to construct thick barriers made of concrete or lead.

(b) is to put the source behind a glare filter.

(c) is to put some physical distance between yourself and the source.

(d) does not exist.

Answers

1. c

2. d

3. d

4. b

5. b

6. d

7. c

8. a

9. c

10. c