Test #5 Physical Science
If the amount of a certain radioactive sample decreases by half in four weeks, in four more weeks the amount remaining should be _____ the original amount
1/4
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
Transuranic elements are those beyond atomic number
92
When U-239 emits a beta particle, the nucleus left behind has
93 protons
the gas in the little girls balloon is made up of former alpha and beta particles produced by radioactive decay. A. If the mixture is electrically neutral how many more beta particles than alpha particles are in the balloon? B. Why is the answer not "same" C. Why are the alpha and beta particles no longer harmful to the child? D. What element does this mixture make?
A. Twice as many Beta particles as Alpha particles B. Alpha particle has double charge; the charge of two beta particles is the same magnitutde as the charge of 1 alpha particle C. They have lost their high KE which is now reduced to thermal energy of random molecular D. Helium, HE
______ are building blocks of matter
Atoms
Which radiation has no electric charge associated with it?
Gamme Rays
Suppose a hydrogen bomb were exploded in a box that could contain all the energy released by the explosion. Copmared to the weight of the box before the explosion the weight of the box after the explosion would be
The same
Its impossible for a hydrogen atom to emit an alpha particle
True
an element will decay to an element with higher atomic number in the periodic table if it emits
a beta particle
Most atoms are as old ________
as the universe
If an alpha particle and a beta particle have the same energy, which particle wil lpenetrate the farthest in an object
beta particle
When a nucleus emits a beta particle, its atomic number
changes, but its mass number remains constant
When an alpha particle is ejected from a nucleus the nucleus then has
charge and mass
energy released by the sun results from the process wherein atomic nuclei
combine
a lone neutron spontaneously decays into a proton plus an __________
electron
The volume of matter comes mostly from its
electrons
When an element undergoes nuclear transmutation, the result is a completely different
element
alpha and beta rays are made of streams of particles whereas gamma rays are streams of ___________
energy (or photons)
Which experiences the least electrical force (zero force) in an electric field
gamma ray
the most abundant element in the universe is
hydrogen
Electrical forces inside a nucleus contribute nuclear
instability
Generally speaking, the larger a nucleus is the greater its
instability
an electrically charged atom is called an ___________
ion
In both fission and fusion, mass
is changed to the form of kinetic energy
Different _______________ of an element are chemically identical but differ in the number of neutrons in the nucleus
isotopes
Compared to the sum of the masses of all the individual nucleons in their seperate states that make up a nucleus the mass of the composite nucleus is
less
When an alpha particle is ejected from a nucleus, the nucleus then hs less
mass and charge
Compared to a neutron bouncing off a carbon nucleus a neutron bouncing off a hydrogen nucleus loses
more speed
When a gamma ray is emitted by a nucleus the nucleus then has appreciably less
neither of these
When a gamma ray is emitted by a nucleus, the nucleus then has appreciable less
neither of these
Different isotopes of an element havve different number of
neutrons
Compared to protons the reason neutrons are effective nucleur bullets in nuclear reations is because a neutron has
none of these
The mass of nucleus is exactl equal to the sum of the masses of its individual
none of these
The atomic mass number of an element is the same as the number of its
nucleons
a nucleon has more mass when it is
outside the nucleus
Atoms are in the state of _______ ________
perpetual motion
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
The source of the earth's natural heat is
radioactive decay in the earth's core
Water from a natural hot spring is warmed by ________ inside the earth
radioactivity
Artificially induced radioactive elements generally have
short half lives
The atom is the _______ particle of an element that has all of the element's chemical properties
smallest
the half life of a radioactive substance is independent of
the age of substance, the number (if large enough) of atoms in the substance, the temperature of the substance, whether the substance exists in an elementary state or in a compound (ALL OF THESE)
The mass of an atomic nucleon is nearly
two thousand times the mass of an electron
A sample of relatively active radioactive material is somewhat
warmer than the evironment
