Unit 2. The Sun, Its Emissions, and the Earth

1.

1 point

(413) In which layer/region of the ionosphere is the highest concentration of electrons located?

F1

E

F2

D

2.

1 point

(414) What phenomena is a dynamic and delicate visual manifestation of solar-induced
geomagnetic storms?

Proton event.

Solar shower.

Geomagnetic storm.

Aurora.

3.

1 point

(404) The basic energy source for the sun is

electromagnetic radiation.

fusion of hydrogen.

thermal radiation.

fusion of helium.

4.

1 point

(406) What is the prime cause of solar activity?

Plages.

Solar flares.

Coronal holes.

Sunspots.

5.

1 point

(410) On what part of the electromagnetic spectrum does the most intense energy fall?

X-ray.

Gamma.

Visible.

Infrared.

6.

1 point

(409) The SFIR monitors solar emissions over a frequency range of

25 to 75 MHz.

245 to 410 MHz.

50 to 100 MHz.

610 to 1,415 MHz.

7.

1 point

(407) The overall polarity of the sun’s northern and southern hemispheres reverse every

11 years.

4 years.

7 years.

22 years.

8.

1 point

(414) What steers electrically charged particles in motion near earth?

Aurora.

Geomagnetic storms.

Magnetic field.

Solar wind.

9.

1 point

Which solar features are ribbon-like, suspended in the corona by the magnetic field, and
comparable to clouds on earth?

Plages.

Flares.

Prominences.

Filaments.

10.

1 point

(414) What space phenomena affect the electrical systems of orbiting satellites?

Radiation.

Differential and bulk charging.

Scintillation.

Atmospheric drag.

11.

1 point

(407) When is the greatest potential for large solar flares to occur?

2 to 3 years following a solar maximum.

During a solar minimum.

During a solar maximum.

2 to 3 years following a solar minimum.

12.

1 point

(410) What electrically charged particles emitted by the sun are of primary interest in the space
environment?

Electrons and protons.

Electrons and gamma rays.

Protons and plasma.

Atoms and molecules.

13.

1 point

The name given to the darkest area at the center of a sunspot is

penumbra.

plasma flow.

plage.

umbra.

14.

1 point

(414) The mechanism by which charged solar particle streams disrupt the magnetosphere and
adversely affect radar, communications, and space operations is

a geomagnetic storm.

a meteor shower.

an aurora.

a proton energy event.

15.

1 point

Which layer of the sun is visible from earth when we look at the sun with our eyes?

Convection zone.

Photosphere.

Corona.

Chromosphere.

16.

1 point

(415) Which solar-geophysical sensor acts like a radar and transmits radio energy vertically over a
range of 2 to 30 MHz or between any two frequencies within this range?

Neutron monitor.

Riometer.

Ionospheric sounder.

Magnetometer.

17.

1 point

(411) The type of radiation that causes ionization of molecules in the upper atmosphere is

infrared.

X-ray.

radio wave.

ultraviolet.

18.

1 point

What form is radiation in when it leaves the sun’s core?

High-energy photons.

X-rays.

Ultraviolet rays.

Gamma rays.

19.

1 point

(415) Which solar-geophysical sensor measures the strengths and variations of earth’s magnetic
field?

Magnetometer.

Riometer.

Neutron monitor.

Ionospheric sounder.

20.

1 point

(408) Which solar feature is formed by the condensation of material from the hot corona?

Filament.

Limb prominence.

Loop prominence.

Eruptive limb prominence.

21.

1 point

(415) Which solar-geophysical sensor measures the absolute TEC by analyzing the signals from
GPS satellites?

Ionospheric sounder.

Transionospheric sensor.

Polarimeter.

Neutron monitor.

22.

1 point

(413) Where are the floating electrons created that make up the ionosphere?

Mesosphere and magnetosphere.

Thermosphere and radiation belts.

Thermosphere and magnetosphere.

Mesosphere and thermosphere.

23.

1 point

(412) The tails of comets that always point away from the sun show the influence of the

magnetosphere.

earth’s magnetic field.

solar wind.

Van Allen radiation belts.

24.

1 point

(415) Which solar-geophysical sensor detects cosmic radio noise at a frequency of 30 MHz?

Neutron monitor.

Riometer.

Magnetometer.

Ionospheric sounder.

25.

1 point

(410) Less than one percent of the sun’s total emitted electromagnetic radiation lies in the

gamma, X-ray, and radio wave portions of the electromagnetic spectrum.

infrared, X-ray, and radio wave portions of the electromagnetic spectrum.

visible, extreme ultraviolet, and X-ray portions of the electromagnetic spectrum.

extreme ultraviolet, X-ray, and radio wave portions of the electromagnetic spectrum.

26.

1 point

(404) How much energy does the sun manufacture per second?

3.85 × 10^24 watts.

3.85 × 10^22 watts.

3.85 × 10^26 watts.

3.85 × 10^28 watts.

27.

1 point

The unit of measurement used to identify the strength of a magnetic field is

an angstrom.

a lux.

a megahertz.

a gauss.

28.

1 point

(411) Which type of radiation has the least application in the space environment?

Ultraviolet.

X-ray.

Infrared.

Radio wave.

29.

1 point

(406) What is the term used to describe transient, concentrated, localized, magnetic fields in the
chromosphere?

Solar flares.

Plage.

Sunspots.

Plasma.

30.

1 point

(407) Which statement is correct regarding the solar cycle?

There is a rapid 4-year rise to a solar maximum followed by a gradual 9-year decline to a solar minimum.

There is a gradual 9-year rise to a solar maximum followed by a rapid 4-year decline to a solar minimum.

There is a gradual 7-year rise to a solar maximum followed by a rapid 4-year decline to a solar minimum.

There is a rapid 4-year rise to a solar maximum followed by a gradual 7-year decline to a solar minimum.

31.

1 point

(411) Which type of radiation causes ionization of upper atmospheric atoms and molecules and
results in the heating of the upper atmosphere?

X-ray.

Ultraviolet.

Radio wave.

Infrared.

32.

1 point

(414) The term used to describe the event in which earth is showered with energetic solar particles
released from a solar flare site is

aurora.

geomagnetic storm.

solar shower.

proton event.

33.

1 point

(404) Select the statement that is the best definition of space environmental effects.

Atoms, molecules, and electrically charged particles and their interactions with earth’s magnetic field.

Atoms and molecules being heated by the sun’s visible radiation, and the various phenomena that is created as a result of earth’s magnetic field.

Electrically charged particles and electromagnetic radiation emitted primarily by the sun, and the environmental phenomena they create by interacting with earth’s upper atmosphere and magnetic field.

Electrically charged particles such as electrons, electromagnetic radiation such as radio waves, and the various phenomena they create within earth’s stratosphere.

34.

1 point

(406) An intense, temporary release of energy that occurs in the vicinity of sunspots and/or plages
is called a

stratospheric storm.

sunspot.

geomagnetic storm.

solar flare.