Physics 110

Introduction to Astronomy

Practice for Exam #3

This is designed for students taking the Physics 110 course at California State University at Bakersfield. Anyone is welcome to attempt the problems. Answers can be found in the pop-up boxes following each question.

These questions cover the material for our second exam, covering the sun and stars.

(Q1)WHICH OF THE FOLLOWING MAIN-SEQUENCE STARS WOULD BE THE SMALLEST AND MOST RED IN COLOR?

(a) B3

(b) G2

(c) K8

(d) O5

And The Answer Is (c) K8

(Q2) THE APPROXIMATE TEMPERATURE OF THE SUN'S "SURFACE" IS

(a) 5800 K

(b) 1-2 million K

(c) 8-10 million K

(d) 1.99 x 10^30 K

And The Answer Is (a) 5800 K

(Q3) A PULSAR IS A ROTATING

(a) black hole.

(b) black dwarf.

(c) neutron star.

(d) white dwarf.

And The Answer Is (c) neutron star

(Q4) AFTER A STAR'S CORE RUNS OUT OF FUEL, THE TEMPERATURE WILL GO UP. WHY DOES THE TEMPERATURE RISE? BECAUSE OF

(a) chemical reactions between elements.

(b) electron degeneracy.

(c) gravitational contraction.

(d) leftover radioactive elements.

And The Answer Is (c) gravitation

(Q5) OUR SUN IS

(a) about half-way through its main-sequence lifetime.

(b) near the end of its main-sequence lifetime.

(c) near the start of its main-sequence lifetime.

(d) not yet a main-sequence star but will be soon (in about 10 million years).

And The Answer Is (a) half-way

(Q6) A STAR THAT GOES NOVA MIGHT LATER BECOME A

(a) Planetary Nebula.

(b) Pulsar.

(c) Type I Supernova.

(d) Type II Supernova.

And The Answer Is (c) Type I SN

(Q7) "THE RATE AT WHICH AN OBJECT EMITS RADIATION INCREASES RAPIDLY AS THE TEMPERATURE OF THE OBJECT INCREASES" IS A STATEMENT OF

(a) Newton's version of Kepler's Third Law.

(b) the Hertzsprung-Russell law.

(c) the inverse-square law.

(d) the Stefan-Boltzmann law.

And The Answer Is (d) Stefan-Boltz.

(Q8) TO GET INTO SPACE FROM THE CORE, THE SUN'S ENERGY HAS TO PASS THROUGH THE

(a) degenerate neutrino compression.

(b) electron and positron layers.

(c) nebula and chromostatic clouds.

(d) radiation and convection zones.

And The Answer Is (d) rad. & conv.

(Q9) THE FUSION PROCESS THAT POWERS MAIN-SEQUENCE STARS TURNS

(a) carbon, nitrogen, and oxygen into iron.

(b) helium into carbon, nitrogen, and oxygen.

(c) hydrogen into helium.

(d) silicon into iron.

And The Answer Is (c) H into He

And now for a sample math question:

(Q10) IN ITS SIMPLEST FORM, THE TOTAL MASS OF STARS IN A BINARY SYSTEM CAN BE FOUND USING THE EQUATION

M + m = a^3/p^2

WHERE THE MASSES ARE IN UNITS OF SOLAR MASSES, a IS THE AVERAGE DISTANCE BETWEEN THE STARS IN AU, AND p IS THE ORBITAL PERIOD OF THE STARS IN YEARS.

IF A BINARY SYSTEM HAS a = 10 AU AND p = 5 YEARS, WHAT IS THE TOTAL MASS OF THE BINARY SYSTEM IN SOLAR MASSES?

(a) 0.025

(b) 0.8

(c) 32

(d) 40

And The Answer Is (d) 40

There will also be a math question taken directly from the homework, identical except that the numbers will be changed.

Astronomy Homepage

Try Exam #1 Practice

Try Exam #2 Practice