PHY 108 - Study Questions Set 1
1. The idea of thermonuclear fusion, the release of energy following the conversion of hydrogen nuclei into a helium nucleus, was first suggested as the source of energy in
A.the interior of Earth.
B.the central core of the Sun.
C.a weapon of mass destruction.
D.a controllable nuclear power station.


2. One astronomical unit, or one AU is defined as the
A.distance traveled by light in one year.
B.mean distance between the Sun and the Earth.
C.distance from which Earth-Sun distance will subtend an angle of one arcsecond.
D.distance traveled by light in one second.


3. What is the distance between Earth and the nearest star? (THINK carefully about your answer!) (Check the list of stars in the Appendix 4 of Freedman and Kaufmann, Universe, 6th ed.)
A.5.2 AU
B.4.3 parsecs
C.1 AU
D.4.3 light-years


4. Which of the following statements best represents the overall rationale for scientific investigation?
A.Reality is comprehensible, and a limited number of fundamental principles govern the nature and behavior of the universe.
B.There are certain patterns in nature from which future events can be predicted, but there are no underlying basic principles or laws.
C.The universe is a hodgepodge of unrelated things behaving in unpredictable ways, but we must continue to observe it in case this behavior threatens Earth.
D.The behavior of the whole universe is governed by our observation of it in such a way as to hide the fundamental truth.


5. Describing a star as being in the constellation Cygnus (the Swan) tells a modern astronomer that the star is
A.in a distant galaxy located in a particular direction from the Earth.
B.inside our solar system.
C.somewhere in a particular region of sky having definite boundaries.
D.one of a set of bright stars that make up a particular "picture" in the sky.


6. Diurnal motion of objects in the sky is caused by the
A.precession of the Earth's axis.
B.revolution of Earth around the Sun.
C.motion of the Moon across the sky.
D.rotation of the Earth on its axis.


7. When we watch the nighttime sky, we find that
A.the stars and constellations remain fixed in our sky, not rising or setting in a time as short as one night because they are so far away.
B.stars and constellations slowly rise in the west, pass overhead, and set in the east.
C.all stars and constellations reach their highest point in the sky at midnight.
D.stars and constellations slowly rise in the east, pass overhead, and set in the west.


8. The celestial equator is defined as the
A.line in the sky that is perpendicular to the Earth's spin axis.
B.line traced in our sky by the Moon each month against the background stars.
C.line traced in our sky by the Sun over one year against the background stars.
D.band of constellations through which the Sun and Moon move in our sky.


9. As the Earth rotates, the zenith of a person standing on the equator sweeps out
A.a path between north and south poles, along the observer's celestial meridian.
B.the celestial equator.
C.a variable path across the sky within the zodiac but not always on the celestial equator.
D.the ecliptic plane.


10. The angle between an observer's horizon and the north celestial pole is governed by
A.latitude.
B.local time.
C.sidereal time.
D.longitude.


11. The declination angle between the north celestial pole and the celestial equator is
A.360°.
B.89° because of the displacement of the Pole Star.
C.180°.
D.90°.


12. The right ascension of a star is one coordinate of its position, measured along the
A.observer's meridian.
B.celestial equator.
C.observer's horizon.
D.ecliptic.


13. The ecliptic is defined as the
A.band of constellations through which the Sun and Moon move in our sky.
B.line in the sky that is perpendicular to the Earth's spin axis.
C.line traced in our sky by the Moon each month against the background stars.
D.line traced in our sky by the Sun over one year against the background stars.


14. If the Earth's spin axis were perpendicular to the Earth's orbital plane (the ecliptic plane), then the seasons and seasonal variation would be
A.very little different from the present seasons.
B.much faster (shorter seasons), but less severe.
C.much more severe.
D.nonexistent.


15. Summertime in the northern hemisphere is when
A.the Sun is closest to the Earth.
B.the Sun is closest to the ecliptic.
C.the Moon is closest to the Earth.
D.more direct sunlight shines on this hemisphere.


16. Twice per year, when day and night are equal in length, the Sun is at one of two positions in the sky known as equinoxes. These points are the intersections of which two planes in the sky?
A.ecliptic and celestial meridian
B.ecliptic and arctic circle
C.celestial meridian and celestial equator
D.celestial equator and ecliptic


17. Precession is
A.the motion of the Earth along its orbital path.
B.a very slow conical motion of the Earth's axis of rotation.
C.the occasional reversal of the direction of spin of the Earth.
D.the daily spinning motion of the Earth.


18. The phenomenon of precession of the Earth's spin axis is caused by the
A.varying intensity of sunlight on Earth throughout the year.
B.tidal ebb and flow of ocean waters on Earth.
C.variation of the spin rate of Earth.
D.gravitational pull of Moon and Sun on the Earth's equatorial bulge.


19. The center, or fixed point, of the Greek model of the universe was
A.the center of the galaxy.
B.close to Earth's center.
C.a point midway between Earth and Sun.
D.the Sun's center.


20. Planets move past the background stars as seen by someone on Earth. What is the normal direction of this motion?
A.east to west because of the motion of the planet along its orbit
B.east to west because of the rotation of Earth
C.west to east because of the motion of the planet along its orbit
D.west to east because of the motion of Earth along its orbit


21. Retrograde motion of a planet against the background stars is always
A.movement northward away from the ecliptic plane.
B.movement from west to east.
C.movement from east to west.
D.the apparent motion of the planet away from Earth.


22. The purpose of describing planetary orbits in terms of epicycles and deferents was to account for the
A.generally eastward motion of a planet compared to background stars while the whole sky appeared to move westward.
B.variation of brightness of a planet with time.
C.difference between the sidereal period and the synodic period of a planet.
D.pattern of direct and retrograde motion of a planet as it moved slowly against the background of stars.


23. Retrograde motion of a planet when viewed from Earth is caused by the fact that the
A.Sun is moving.
B.planet's orbit is inclined at an angle to Earth's orbit.
C.Earth is moving.
D.planet's orbit is elliptical.


24. Which of the following objects cannot transit (pass in front of) the Sun when viewed from Earth?
A.Mars
B.Venus
C.the Moon
D.Mercury


25. What is the difference between the synodic and sidereal periods of a planet?
A.There is no difference; they are one and the same time period. The synodic period is the name used in the geocentric theory, while the sidereal period is the name used in the heliocentric theory.
B.The synodic period refers to the planet's period with respect to Earth's motion, while the sidereal period is the true period with respect to the background stars.
C.The synodic period refers to the planet's rotation around its axis, while the sidereal period is the time for one orbit.
D.The synodic period refers to the planet's motion with respect to the background stars, while the sidereal period is the true period with respect to Earth's motion.


26. The reason why Copernicus' heliocentric theory soon came to be regarded as preferable to the geocentric theory of Ptolemy is that the heliocentric theory
A.accounted for the same observed motions of the planets as the geocentric theory but did so much more accurately.
B.used complex constructions called epicycles and deferents to account for the observed motions of the planets and so was considered more reliable than the geocentric theory.
C.accounted for the same observed motions of the planets as the geocentric theory but did so in a much simpler way.
D.accounted for retrograde motion, which the geocentric theory was unable to explain.


27. How many moons of Jupiter were seen by Galileo?
A.4
B.12
C.1
D.0


28. The Kepler model of the solar system is
A.Sun-centered, with planets moving in circles around it.
B.Earth-centered, with Sun, Moon, and planets moving in ellipses in the sky.
C.Earth-centered, with planets describing epicycles in the sky.
D.Sun-centered, with elliptical planetary orbits.


29. Kepler's laws describe the
A.motions of the planets around the Sun.
B.motion of the spin axis of Earth over long time periods.
C.motions of the planets around Earth.
D.motion of the Moon around the Sun.


30. What was the MOST IMPORTANT contribution of Newton to the development of astronomy?
A.He showed that astronomical phenomena can be explained using only basic physics and mathematics.
B.He was the first person to observe the sky through a telescope.
C.He showed that planetary orbits are ellipses, with the planets moving fastest when closest to the Sun.
D.He invented the refracting telescope.


31. To define an object's velocity, we need to specify
A.how fast it is moving and also its mass.
B.only in which direction it is moving.
C.only how fast it is moving.
D.how fast it is moving and also in which direction it is moving.


32. An object orbiting the Sun in a circle can be said to be
A.always accelerating.
B.moving under the action of equal and opposite forces.
C.weightless.
D.moving at a constant velocity.


33. If you were to be sent to the Moon, which of your physical properties would be altered noticeably?
A.weight
B.height
C.mass
D.volume


34. When an object moves uniformly at a constant speed in a circle, the acceleration of the object is always
A.outward, away from the center of the circle.
B.zero; the object is not accelerating, since it is moving uniformly at a constant speed.
C.inward, toward the center of the circle.
D.along the direction of the path, tangential to the circle.


35. If two massive bodies, initially held at rest in space, are released, then they will begin to
A.move in elliptical orbits around one another.
B.orbit one another in circles.
C.move away from each other with constant acceleration.
D.move toward one another.


36. The law of gravitation expounded by Newton for the force F between two objects of masses M and m with separation (between centers) of R is given, with G being a constant, by
A.F = GMm/R2
B.F = GMmR2
C.F = Mm/GR2
D.F = GM/mR2


37. Suppose that a planet of the same mass as Earth were orbiting the Sun at a distance of 10 AU. The gravitational force on this planet due to the Sun would be
A.100 times the gravitational force the Sun exerts on Earth.
B.10 times the gravitational force the Sun exerts on Earth.
C.1/10 of the gravitational force the Sun exerts on Earth.
D.1/100 of the gravitational force the Sun exerts on Earth.


38. A person orbiting Earth in the Space Shuttle feels weightless because
A.only one force (gravity) acts on her, but gravity also accelerates the shuttle so that the shuttle does not push up on her to create the feeling of weight within it.
B.two forces are acting on her in opposite directions, so they cancel and produce the same effect as if no force at all were acting.
C.her mass is zero in space, and weight requires mass.
D.no forces act on her.



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