Module 16 Flashcards
Nuclear Fusion:
The process by which two or more small nuclei fuse to make a bigger nucleus.
Nuclear Fission:
The process by which a large nucleus is split into smaller nuclei.
Critical mass:
the amount of isotope necessary to sustain a chain reaction.
Absolute Magnitude:
the brightness of a star corrected for distance on a scale of -8 to 19 the smaller the number the brighten the star.
Apparent Magnitude:
the brightness of a star as seen in the night sky. The smaller the number the brighter the star.
Light Year:
the distance light could travel along a straight line in one year.
Galaxy:
A large ensemble of stars all interacting through the gravitational force orbiting around a common center.
From the inside to the outside, name the 4 regions of the sun.
Core, radiative zone, convection zone, photosphere.
How does the sun get its power? In which region of the sun does this process occur?
Nuclear Fusion. The Core.
What part of the sun do we see?
The Photosphere
A 251Cf nucleus is bombarded with a neutron. It breaks down into a 124Sn nucleus, a 120 Cd nucleus, and 7 neutron. Is this nuclear fission or nuclear fusion?
Nuclear fission.
Two 4He nuclei collide and turn into a 7Be nucleus and one neutron. Is this nuclear fusion or nuclear fission?
Nuclear Fusion.
For both the nuclear fusion that occurs in the sun and the nuclear fission that occurs in a nuclear power plant, what can we say about the mass of the starting materials compared to the mass of what’s made in the end?
the mass of the starting materials is larger than the mass of the materials the proses makes
Why is it impossible for a nuclear power plant to have a nuclear explosion?
because a power plant does not have significantly mare than the critical mass of the large nucleus that is breaking apart.
Why is a nuclear fusion considered a better option for energy production than nuclear fission?
Nuclear fusion is a better means of production because there are no radioactive byproducts, there is no chance of meltdown , and the starting materials are cheap.
If nuclear fusion is a better option, why don’t we use it?
We cannot use nuclear fusion yet because we cannot master the technology to make it economically feasible?
the H-R diagram in order top bottom is:
Super Giants, Red Giants, Main sequence, White Dwarfs
Which of the stars is most like our sun?
The main sequence stars
Order the 4 star types in terms of increasing size.
White dwarfs, Main sequence, Red Giants, Super Giants
IMPORTANT : Order the 4 star types in terms of increasing brightness.
Supergiant, red giants, main sequence stars, white dwarfs
Which of the star types are the coolest?
Red Giants
What similarity exists among novas, supernovas, and pulsating variables?
They are all variable stars types, thus their brightness changes radically with time.
What is the big difference among novas, supernovas, and pulsating variables?
it is their lifetime. Pulsating stars last a long time, supernovas exist very briefly, and novas are somewhere in between.
What most likely formed the crab nebula?
A supernova
What are the 2 methods for measuring the distance from Earth to a star? Which of the 2 is the most accurate? Which can be used to measure long distances?
The Parallax Method and the apparent magnitude method. The Parallax Method is the most accurate. the apparent magnitude method can be used to measure long distances.
Why are Cepheid variables so important for measuring long distances in the universe?
Because they seem to have a relationship between their period and their magnitude that allows them to be used in the apparent magnitude method for measuring long distances in the universe.
What are the 4 basic types of galaxies? to which type does the Milky War belong?
Spiral, Lenticular, Elliptical, and Irregular Galaxies.
Spiral Galaxy.
Stars group together to form ________, which group together to form _______, Which group together to form _______, some of which group together to form _______.
Galaxies
Groups
Clusters
Super Clusters
For the first 3 answers you gave in question 22, give the names that apply to those in which Earth’s Solar system Belongs
Milky Way
Local Group
Virgo Cluster
Why do most astronomers believe the universe in expanding?
because the light form nearly every galaxy experiences a red shift before it reaches the earth, and the red shift increases the farther the galaxy is from the earth.
If the universe is expanding, does the geometry of the expansion matter? If so, why
Yes because the theories that can be developed for the formation of the universe depend on that initial assumption.
A scientist studies a process in which a neutron strikes a 216Pu nucleus to make a 104Cd nucleus, a 110Pd nucleus, and 3 neutrons. If the scientists measures the mass of the 216Pu nucleus and the original neutron and then subtracts the mass of the 104Cd nucleus, the mass of the 110Pd nucleus, and the mass of the three neutrons, will the scientist get a positive number, a negative number, or zero?
positive number. (Because the mass of the starting materials is larger than the mass of the materials the proses makes)
What is red shift?
it is the phenomenon in which light that comes to the earth from other galaxies winds up having longer wavelengths than it should.
