Top Hat Monacle Questions Lecture 4 16 Viruses What characteristics of life do viruses not have Which of the following makes viruses in between living and non living organisms A ability to react to environment B ability to grow by taking in nourishment and processing it into energy C ability to reproduce with offspring having some characteristics of parent D ability to evolve Answer B or C Life in solar system Where in our solar system other than Earth is there a small chance that life exists A Venus B Mars C Europa moon of Jupiter D Titan moon of Saturn E Callisto moon of Jupiter Answer B C D Rate of Star Formation How many stars per year have been formed on average in the Milky Way since its formation Hydrogen helium ratio What should be the ratio by mass of hydrogen to helium in the Universe A 1 000 B 100 C 10 D 1 E less than 1 Answer C Lecture 4 11 A 7 1 B 6 1 C 4 1 D 3 1 E 2 1 Answer D Hubble s Law How far away is a galaxy with a recessional speed of 40 000 km s Lecture 4 9 A 400 Mpc B 575 Mpc C 750 Mpc D 925 Mpc Answer B Tutorial 4 6 A 10 pc B 30 pc C 90 pc D 800 pc Answer C Answer B Lecture 4 4 RR Lyrae Star How far away is an RR Lyrae star that appears as bright as the Sun would be at 10 parsecs Cepheid variable star A Cepheid variable star with a period of 20 days appears 100 times brighter than the Sun would be at 10 parsecs How far away is it Density of a neutron star What it the density of a 1 5 solar mass neutron star of radius 10 km Vsphere 4 R3 3 A 7 2 x 1026 kg m3 B 2 3 x 1018 kg m3 C 7 2 x 1017 kg m3 D 2 4 x 1017 kg m3 Answer C Grain of neutron star material What is the mass of a 1 mm grain of neutron star material A 720 million kg B 720 000 kg C 720 kg Answer A Twin paradox How much older are you than your twin who visits Proxima Centauri in a 0 8 c spaceship Your twin gets in a spaceship and heads to the nearest star Proxima Centauri 4 3 light years away orbits it for a year and then heads home Both interstellar journeys are made at v 0 8 c How much older are you than your twin when she returns A you are the same age B 2 9 years C 5 7 years D 4 7 years Answer D Cosmic ray muons How far do muons made by cosmic rays in the upper atmosphere travel in their 2 2 microsecond lifetime if they are moving at v 0 9999 c When at rest in the lab a muon a heavy electron has a lifetime of 2 2 microseconds 2 2 x 10 6 s for its weak decay to an electron and a neutrino Muons are made by collisions of cosmic rays with atomic nuclei in the upper atmosphere Without time dilation even if they are traveling at v 0 9999 c they should only travel d v t 3 0 x 108 m s 2 2 x 10 6 s 660 m before they decay and so would not reach us With time dilation how far do they travel before decaying A 6600 km B 66 km C 47 km Answer C Lecture 3 28 Neutrinos from a core collapse supernova Assume that an 8 solar mass star collapses and that half of its mass is protons If all of these protons combine with electrons to form neutrons during the collapse via the electron capture process how many neutrinos are emitted The Sun s mass is 2 0 x 1030 kg and one mole NA 6 0 x 1023 of protons has a mass of 1 0 g A 1 3 x 1010 B 4 8 x 1054 C 9 6 x 1054 D 4 8 x 1057 Answer D Lifetime of 10 solar mass star What is the lifetime of a 10 solar mass star The Sun s lifetime is 10 billion years A 10 billion years B 1 billion years C 100 million years D 10 million years E 1 million years Answer D Lecture 3 26 Fusion rate in stars How does the rate of nuclear fusion in a high mass star compare to that in a low mass star A greater than B equal to C less than Answer A Lifetimes of main sequence stars If Star A has the same mass as the Sun and Star B has 6 times the mass of the Sun how do their lifetimes compare A A lives less than 1 6 as long as B B A lives 1 6 as long as B C A has the same lifetime as B D A will lives 6 times longer than B E A will live more than 6 times longer than B Answer E Fusion rate of two solar mass star How does the rate of hydrogen fusion to helium of a star with twice the mass of the Sun compare to that of the Sun A smaller B the same C a little larger D twice E more than twice Answer E Density of a white dwarf How many pieces of a white dwarf star the size of grains of sand cubes of side 1 mm could you lift without the risk of injury White dwarf Density 106 g cm3 A 1 B 10 C 100 D 1 000 E 10 000 Answer B or C Lecture 3 21 Properties of nearby stars How do we know the absolute magnitude luminosity of a nearby star its surface temperature and its radius What in order would you use to find these Define 1 spectral class 2 apparent magnitude brightness seen from Earth 3 distance from the Sun from parallax and apparent magnitude 4 absolute magnitude and temperature A 4 1 2 B 3 4 2 C 3 1 4 D 2 3 4 Answer C Arcturus Luminosity Arcturus Bo tes is known from the width of its absorption spectrum lines to be a class III red giant and from its black body spectrum we know its surface temperature is 4300 K Its luminosity is in units of the Sun s luminosity closest to A 1 B 2 C 10 D 100 E 1 000 Answer C Lecture 3 19 The full Moon has an apparent magnitude of 12 6 and when Mars is brightest in the night sky its apparent magnitude is 2 0 Apparent magnitude Q1 Which has the largest apparent magnitude number A Full Moon B Mars Answer B Apparent magnitude Q2 Which object will look brighter from Earth A Full Moon B Mars Answer A Apparent magnitude Q3 If a new object was discovered that looked even dimmer from Earth than Mars what could its apparent …
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