PHY1000 Chapter 33
A certain radioactive isotope placed near a Geiger counter registers 120 counts per minute. If the half-life of the isotope is one day, what will the count rate be at the end of four days?
7.5 counts/min
An element will decay to an element with higher atomic number in the periodic table if it emits
a beta particle.
When a nucleus emits a beta particle, its atomic number
changes, but its mass number remains constant.
When a beta particle is ejected from a nucleus, the nucleus then has a greater
charge
The sources of X-rays and gamma rays, respectively, are
electron clouds and the atomic nucleus.
Which radiation has no electric charge associated with it?
gamma rays
X-rays are similar to
gamma rays
There is a greater proportion of carbon 14 in
new bones
Electric forces within an atomic nucleus tend to
push it apart.
The high temperature of the Earth's interior is due mostly to
radioactivity.
The half-life of a radioactive substance is INDEPENDENT of
the age of the substance. the temperature of the substance. the number (if large enough) of atoms in the substance. whether the substance exists in an elementary state or in a compound. all of these
Most of the radioactivity we personally encounter comes from
the natural environment.
When thorium (A = 90) emits a beta particle, the resulting nucleus has atomic number
none
The atomic mass number of an element is the same as the number of its
nucleons.
The half-life of an isotope is one day. At the end of two days the amount that remains is
one-quarter
