PHYS 1320 CH. 33
Suppose the half-life of a material is 10 days. You have one 1 kg of the material today. How much of the material would you have after 10 days and 20 days, respectively?
0.5 kg after 10 days, and 0.25 kg after 20 days
The half-life of carbon 14 is 5730 years. If a 1-gram sample of old carbon is 1/8 as radioactive as 1-gram of a current sample, then the age of the old sample is about
17,200 years.
A material has a half-life of 1 day. If 2 kg of this material is available today, how much of it was available yesterday, and how much the day before?
4kg yesterday, and 8 kg the day before
When radium (A = 88) emits an alpha particle, the resulting nucleus has atomic number
86
Which of the following isotopes is radioactive?
Carbon-14
Suppose 2 kg of a material has a half-life of 1 day. After how long will NONE of the material remain?
Never
It's impossible for a hydrogen atom to emit an alpha particle.
True
The discovery of radioactivity closely followed the discovery of _______.
X-rays
An element that undergoes radioactive decay becomes _______.
an entirely different element
An atom with an imbalance of electrons to protons is
an ion.
If an alpha particle and a beta particle have the same energy, which particle will penetrate farther into an object?
beta particle
When an alpha particle is ejected from a nucleus, the nucleus then has less
both of these; charge & mass.
When a nucleus emits a beta particle, its atomic number
changes, but its mass number remains constant.
Which of these ejects the greatest amount of dangerous radiation into the atmosphere?
coal-fired power plants
The sources of X-rays and gamma rays, respectively, are
electron clouds and the atomic nucleus.
When a gamma ray is emitted by a nucleus, the nucleus then has less
energy.
Which type of radiation - alpha, beta, or gamma - predominates within an enclosed elevator descending into a uranium mine?
gamma
Which of these is electromagnetic radiation?
gamma radiation
Which radiation has no electric charge associated with it?
gamma rays
X-rays are most similar to which of the following - alpha, beta, or gamma rays?
gamma rays
X-rays are similar to
gamma rays.
X-rays may be regarded as
high frequency radio waves.
Generally speaking, the larger a nucleus is, the greater its
instability.
All the uranium in today's deposits in the future will become _______.
lead
The fate of the world's uranium supply is to eventually become
lead.
Different isotopes of an element have different numbers of
neutrons
There is a greater proportion of carbon 14 in
new bones.
Carbon-14 in the atmosphere is transformed from _______.
nitrogen
When thorium (A = 90) emits a beta particle, the resulting nucleus has atomic number
none of these
Which of these makes up the least radiation in the everyday environment?
nuclear power plants
The atomic mass number of an element is the same as the number of its
nucleons.
If a certain isotope has a radioactive half-life of 10 years, how much of the isotope will remain at the end of 20 years?
one quarter
The half-life on an isotope is one day. At the end of three days, how much of the isotope remains?
one-eighth
The strong force is one of the four fundamental forces in nature, and exists _______.
only between particles in the nucleus
Carbon dating requires that the object being tested contain
organic material.
The atomic number of an element is the same as the number of its
protons.
Electric forces within an atomic nucleus tend to
push it apart.
When a beta particle is ejected from a nucleus, the nucleus then has slightly
smaller mass and significantly greater charge.
The mass of an atomic nucleon is nearly
two thousand times the mass of an electron.