ASTR 101, Fall 2001 Test 1
(for solutions, click on the link at the bottom of the page)

(1) What is light made of?
a. Fast moving air molecules.
b. Intangible ether particles.
c. Small pieces of the surfaces of hot objects.
d. Waves made up of electric and magnetic fields.

(2) What is the difference between red light and blue light?
a. Red light is emitted by hot objects, blue light by cold ones.
b. Red light has a longer wavelength than blue light.
c. Red light travels slower than blue light.
d. The only difference is the direction in which the waves oscillate.

(3) The Earth's atmosphere shields us from electromagnetic radiation, with the exception of
a. Visible light only.
b. Visible light and radio waves.
c. X-rays and UV radiation.
d. X-rays and gamma rays.

(4) When a solid body is heated to high temperatures one obtains from it
a. A continuous spectrum.
b. A line spectrum.
c. An emission line.
d. An absorption line.

(5) The positively charged particle contained within the core of an atom is the
a. Electron.
b. Ion.
c. Neutron.
d. Proton.

(6) In a spectrum, dark bands set against a bright background are called
a. Absorption lines.
b. Emission lines.
c. Continuum lines.
d. Doppler lines.

(7) What are ions?
a. Small particles contained inside the nuclei of atoms.
b. Atoms with missing electrons, or extra electrons.
c. Individual packets of radio waves, similar to photons for light.
d. Particles that have not yet been identified.

(8) How many electrons does a neutral hydrogen atom have?
a. 0.
b. 1.
c. 2.
d. 4.

(9) What happens inside an atom when it emits a photon of light?
a. An electron jumps from a higher energy state to a lower one.
b. The atom loses one or more electrons.
c. The motion of the electrons along their orbits slows down.
d. The nucleus of the atom cools down and shrinks.

(10) What kind of spectrum do we get from a star like the Sun?
a. An emission line spectrum.
b. An absorption line spectrum.
c. A continuous emission spectrum.
d. A continuous absorption spectrum.

(11) Why are mountaintops better than low elevations for telescopes?
a. They have a smaller layer of atmosphere above them.
b. The weather is colder, which improves the instruments' performance.
c. They are not as noisy as locations at lower elevation.
d. The distance to the objects the telescopes are looking at is smaller.

(12) What is the resolution of a telescope?
a. Its ability to collect light and produce bright images.
b. The magnification of the images it produces.
c. Its ability to detect fine detail and produce sharp images.
d. The number of spectral lines one can see with it.

(13) What is the main reason the Hubble Telescope gives great images?
a. It is in orbit above the atmosphere.
b. It has the largest mirror ever built.
c. It has the most perfect mirror ever built.
d. It has the most sophisticated instruments.

(14) Which of the following affects a telescope's magnification?
a. The wavelength of the light.
b. The surface area of the main mirror.
c. The focal length of the eyepiece lens.
d. The elevation of the telescope above sea level.

(15) What is a reflecting telescope?
a. One that focuses the incoming light with a mirror rather a lens.
b. One that uses extra mirrors to collect more light on the primary lens.
c. One that gives inverted images of the objects seen through it.
d. One that produces negative images (dark stars on light backgrounds).

(16) Which of the following is an advantage of reflecting vs refracting telescopes?
a. Large reflecting telescopes are much easier to build and support.
b. Refracting telescopes cannot collect as many different kinds of light.
c. Images produced by refracting telescopes are inverted instead of upright.
d. Stars stand out better in images produced by reflecting telescopes.

(17) Can we use X-ray telescopes from the Earth's surface?
a. Yes, because X-rays penetrate easily through the atmosphere. 
b. Yes, provided they are placed on high mountains.
c. Yes, provided they are shielded from ordinary light.
d. No, we need to put them on rockets, balloons or satellites.

(18) Why are some infrared telescopes used on airplanes in flight?
a. Because on the ground they would be too affected by vibrations.
b. Because IR radiation is absorbed to a large extent by the atmosphere.
c. Because objects emitting IR radiation are further away in space.
d. Because on the ground there is too much light pollution.

(19) For which of the following can we often use the same detectors as for regular light?
a. Radio waves.
b. IR and UV radiation.
c. X-rays.
d. Gamma rays.

(20) What kind of telescope would you use to look at cool planets and interstellar clouds?
a. Radio.
b. Infrared.
c. Ultraviolet.
d. X-ray.

(21) At what time will a full Moon rise above the horizon?
a. Noon.
b. Sunset.
c. Midnight.
d. The answer depends on the time of year.

(22) What is the zenith?
a. The time at which the Moon is highest in the sky.
b. The point straight above us on the celestial sphere.
c. The line along which the Sun moves on the celestial sphere.
d. A small circle on which a planet moves according to the geocentric model.

(23) The day of the year in which the Sun is highest in the sky is called
a. Vernal (Spring) equinox.
b. Autumnal (Fall) equinox.
c. Summer solstice.
d. Winter solstice.

(24) What are seasons on Earth due to?
a. Changes in the distance between the Sun and Earth.
b. The tilt of the Earth's axis with respect to its orbit.
c. The influence of the Moon on the Earth's motion.
d. The location of the other planets in the solar system.

(25) Why is the first quarter Moon shaped like a half circle?
a. The Moon changes shape, and at that time it is not round.
b. The Earth's shadow covers the rest of the Moon's surface.
c. The Sun illuminates only that portion of the Moon's surface.
d. Some of the Moon's illuminated surface is turned away from us.

(26) If you were on the Moon facing the Earth, would you see different Earth phases?
a. No, because the Earth spins around its axis.
b. No, because the Earth is larger than the Moon.
c. Yes, but not all of the phases.
d. Yes.

(27) Deneb is the brightest star in its constellation; what constellation is it in?
a. Orion.
b. The Big Dipper.
c. Cygnus.
d. Andromeda.

(28) The star Altair is the brightest star in the constellation Aquila; so its designation is
a. A Aquilae.
b. a Aquilae.
c. 1 Aquilae.
d. Aquila prime.

(29) Vega is of magnitude 0.03, Altair 0.77, and Deneb 1.25; which is the brightest star?
a. Vega.
b. Altair.
c. Deneb.
d. Cannot be determined from the given information.

(30) If you wanted to determine the temperature of a star, what would you look at?
a. The magnitude of the star.
b. The peak of the star's spectrum.
c. The Doppler shift of the star.
d. The declination of the star.

(31) What point of view did the ancient Greeks contribute to astronomy?
a. The need to predict seasonal changes.
b. The need to represent astronomical objects in their art.
c. The need to interpret the meaning of events such as eclipses.
d. The need to model the solar system, in order to understand it.

(32) Why is Ptolemy important in the history of astronomy?
a. He proposed more than 2000 years ago that the Earth revolves around the Sun.
b. He was the first person who counted all the stars in the sky.
c. He developed a very detailed and successful geocentric model of the solar system. 
d. He made the best observations in astronomy before the telescope was invented.

(33) What kind of model for the solar system was most common in antiquity?
a. A heliocentric model.
b. A geocentric model.
c. A gravitational model.
d. A celestial model.

(34) What is an epicycle?
a. A full cycle of seasons on Earth due to the tilt of its rotation axis.
b. A small circle superimposed on a planet's larger, main circular orbit.
c. The center of the circle along which a planet moves around the Sun.
d. One of the circles that are used to divide the celestial sphere into sectors.

(35) How do we call the occasional backward drift of planets on the celestial sphere?
a. Heliacal rising.
b. Retrograde motion.
c. Wandering.
d. Primum mobile.

(36) What kind of telescope did Tycho Brahe use?
a. He did not have a telescope.
b. A refracting telescope.
c. A reflecting telescope.
d. A diffracting telescope.

(37) Why was Tycho's observation of a supernova important?
a. Because it was the first time ever a supernova was recorded.
b. Because it showed that distant objects, beyond the Moon, can change.
c. Because it was evidence in support of the geocentric model.
d. Because it showed how good his observational techniques were.

(38) How does Copernicus' model of the solar system differ from our present ideas?
a. Copernicus' model was geocentric.
b. Copernicus still used circles and epicycles.
c. In Copernicus' model the Moon also orbits the Sun.
d. In Copernicus' model the universe does not expand.

(39) Around what time did Copernicus and Tycho Brahe live?
a. Around the 5th century BC.
b. Around the 2nd century AD.
c. Around the 1500's.
d. Around the 1800's.

(40) Are your name and test version written in the appropriate places?
a. Yes.
b. No.

Solutions