Astronomy - Exam 1 Practice Questions

Which of the following pairs of atoms describes different isotopes of the same element?

1: an atom of carbon (6 protons, 6 neutrons) with a neutral charge

2: an atom of carbon (6 protons, 6 neutrons), with a positive charge

3: an atom of carbon (6 protons, 8 neutrons), with a neutral charge

4: an atom of nitrogen (7 protons, 8 neutrons), with a neutral charge

(A) 1+2

(B) 2+3

(C) 3+4

(D) none of these atoms are different isotopes of each other

Which of the following pairs of atoms describes different isotopes of the same element?

1: an atom of carbon (6 protons, 6 neutrons) with a neutral charge

2: an atom of carbon (6 protons, 6 neutrons), with a positive charge

3: an atom of carbon (6 protons, 8 neutrons), with a neutral charge

4: an atom of nitrogen (7 protons, 8 neutrons), with a neutral charge

(A) 1+2

(B) 2+3

(C) 3+4

(D) none of these atoms are different isotopes of each other

(B) 2+3

A star with a surface temperature of 2900 K emits the most flux (i.e., is brightest) at a wavelength of about 1000 nm. What wavelength would you expect a star with surface temperature of 29,000 K to emit the most flux?

(A) 10,000 nm

(B) 1000 nm

(C) 100 nm

(C) 100 nm

Which period of time in the history of the Universe was the longest?

(A) the length of time before the Milky Way galaxy formed

(B) the length of time before the Sun formed

(C) the length of time between when the Sun formed and the Earth formed

(D) the length of time between when the Earth formed and when vertebrate animals appeared

(B) the length of time before the Sun formed

(4) The planets in our Solar System that are visible to the unaided human eye in the night sky are Mercury, Venus, Mars, Jupiter, and Saturn. They are listed here in order of increasing distance from the Sun. Which of these planets has the shortest orbital period?

(A) Mercury

(B) Venus

(C) Mars

(D) Jupiter

(E) Saturn

(F) [not enough information is given to determine this answer]

(A) Mercury

Earth's axis of rotation is tiled by _________________ relative to the plane in which it orbits the Sun.

23.5 degrees

Which direction does the Earth rotate?

West to east

Imagine that astronomers discover an exoplanet that has twice the mass of the Earth, which we’ll call “Wulf.”

(a) Wulf orbits 1 AU from its parent star, which has a mass of 1.0 times the mass of the Sun. How long is the orbital period of Wulf?

(b) Now imagine that Wulf is five times more massive than the Earth. How long would its orbital period be?

1 yr, 1 yr

Imagine that you observe the sky from North Carolina, and you see the Moon rising tonight in a "full" phase. Tomorrow, when (qualitatively) would you observe the Moon rising?

answers could include: later than today, ~1 hour after sunset, shortly after sunset

Imagine that you observe the sky all night long from North Carolina, and it is clear, and the ecliptic is above your horizon. Yet you do not observe the Moon at all. What phase is the Moon in?

either "new" or "full" would be acceptable

An asteroid is in an elliptical orbit around the Sun. Its farthest approach from the Sun is called its orbital _________, and at this point it will be moving relatively __________. Its closest approach to the Sun is called its orbital ___________, and at this point it will be moving relatively ____________.

Compared with an asteroid on a highly elliptical orbit, a comet on an elliptical, but nearly circular, orbit around the Sun will experience ___________ changes in its orbital speed.

aphelion, slowly, perihelion, quickly, smaller (or less extreme)

The Earth _________ on its axis once per day and __________ around the Sun once per year.

rotates, revolves (or orbits)

The list below includes items that we have discussed in class. Rank them from 1 to 6, from the smallest number of objects to the largest number of objects in each category, in the parentheses.

( ) the number of stars that an average human can see with ideal sky conditions

( ) the number of planets in our Solar System

( ) the number of stars in our Galaxy

( ) the number of years since the Big Bang

( ) the number of constellations in the zodiac

( ) the number of natural satellites that orbit the Earth that can be seen by humans

4, 2, 6, 5, 3, 1

Place an “X” in the ( ) for all answers that are true: A photon that contributes to the hydrogen (H) line at exactly 656.2797 nm (in the visible part of the spectrum) ...

( ) is absorbed by neutral H atoms

( ) is absorbed by ionized H atoms

( ) is emitted by neutral H atoms

( ) is emitted by ionized H atoms

( ) is absorbed by an electron in a neutral atom of any element

( ) is absorbed by an electron in an ionized atom of any element

( ) is emitted by an electron in an neutral atom of any element

( ) is emitted by an electron in an ionized atom of any element

( ) has a frequency of 656.2797 nm

the first and third options only