1.D In the core of the Sun, hydrogen is fusing into helium. This process does no
ID: 1500446 • Letter: 1
Question
1.D In the core of the Sun, hydrogen is fusing into helium. This process does not occur in planets since the pressure and temperature in planets isn't hot enough. Why does the hydrogen gas have to be very hot, with a high pressure, in order for fusion to occur?
1.A If a radioactive isotope has a 1-year half-life, what fraction will remain after 5 years?
1/5
1/4
1/8
1/16
1/32
1.B Iodine 131 (atomic number 53) commonly decays to Xenon (atomic number 54). What type of decay does iodine undergo?
alpha decay
beta decay
3. gamma decay
Except for hydrogen, helium, and a little lithium, the lower-mass elements (lighter than iron) that are spread throughout the dust of the universe were created
during the fusion process that powers the stars, and then released in supernova explosions.
) in hot white dwarf stars.
during the shock of a supernova explosion.
) in Kansas.
in the original creation of the universe.
1.C When we fission the U-235 nucleus, the total rest-mass of all the resulting fragments of matter
is less than the mass of the original nucleus.
is more than the mass of the original nucleus
is the same as the mass of the original nucleus.
) is turned into broccoli.
5. None of the above.
1.1/5
2.1/4
3.1/8
4.1/16
5.1/32
Explanation / Answer
1A.
Half life of a sample is 1 year.
The sample remain after 1 year is 1/2
The sample remain after second year is 1/4
The sample remain after third year is 1/8
The sample remain after forth year is 1/16
The sample remain after fifth year is 1/32
Therefore, the correct option is (5)
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(1)B
The atomic number will increase after decay only in the beta decay process.
As the atomic number decreases, the decay is beta decay. So correct option is 2
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