Start a chain reaction, or introduce non-radioactive isotopes to prevent one. Control energy production in a nuclear reactor!
Section summary
The binding energy (BE) of a nucleus is the energy needed to separate it into individual protons and neutrons. In terms of atomic masses,
where
is the mass of a hydrogen atom,
is the atomic mass of the nuclide, and
is the mass of a neutron. Patterns in the binding energy per nucleon,
, reveal details of the nuclear force. The larger the
, the more stable the nucleus.
Conceptual questions
Why is the number of neutrons greater than the number of protons in stable nuclei having
greater than about 40, and why is this effect more pronounced for the heaviest nuclei?
Binding energy is a measure of how much work must be done against nuclear forces in order to disassemble a nucleus into its constituent parts. For example, the amount of energy in order to disassemble
into 2 protons and 2 neutrons requires 28.3 MeV of work to be done on the nuclear particles. Describe the force that makes it so difficult to pull a nucleus apart. Would it be accurate to say that the electric force plays a role in the forces within a nucleus? Explain why or why not.
is a loosely bound isotope of hydrogen. Called deuterium or heavy hydrogen, it is stable but relatively rare—it is 0.015% of natural hydrogen. Note that deuterium has
, which should tend to make it more tightly bound, but both are odd numbers. Calculate
, the binding energy per nucleon, for
and compare it with the approximate value obtained from the graph in
[link] .
is among the most tightly bound of all nuclides. It is more than 90% of natural iron. Note that
has even numbers of both protons and neutrons. Calculate
, the binding energy per nucleon, for
and compare it with the approximate value obtained from the graph in
[link] .
is the heaviest stable nuclide, and its
is low compared with medium-mass nuclides. Calculate
, the binding energy per nucleon, for
and compare it with the approximate value obtained from the graph in
[link] .
(a) Calculate
for
, the rarer of the two most common uranium isotopes. (b) Calculate
for
. (Most of uranium is
.) Note that
has even numbers of both protons and neutrons. Is the
of
significantly different from that of
?
(a) Calculate
for
. Stable and relatively tightly bound, this nuclide is most of natural carbon. (b) Calculate
for
. Is the difference in
between
and
significant? One is stable and common, and the other is unstable and rare.
(a) 7.680 MeV, consistent with graph
(b) 7.520 MeV, consistent with graph. Not significantly different from value for
, but sufficiently lower to allow decay into another nuclide that is more tightly bound.
The fact that
is greatest for
near 60 implies that the range of the nuclear force is about the diameter of such nuclides. (a) Calculate the diameter of an
nucleus. (b) Compare
for
and
. The first is one of the most tightly bound nuclides, while the second is larger and less tightly bound.
The purpose of this problem is to show in three ways that the binding energy of the electron in a hydrogen atom is negligible compared with the masses of the proton and electron. (a) Calculate the mass equivalent in u of the 13.6-eV binding energy of an electron in a hydrogen atom, and compare this with the mass of the hydrogen atom obtained from
[link] . (b) Subtract the mass of the proton given in
[link] from the mass of the hydrogen atom given in
[link] . You will find the difference is equal to the electron’s mass to three digits, implying the binding energy is small in comparison. (c) Take the ratio of the binding energy of the electron (13.6 eV) to the energy equivalent of the electron’s mass (0.511 MeV). (d) Discuss how your answers confirm the stated purpose of this problem.
A particle physicist discovers a neutral particle with a mass of 2.02733 u that he assumes is two neutrons bound together. (a) Find the binding energy. (b) What is unreasonable about this result? (c) What assumptions are unreasonable or inconsistent?
(a)
(b) The negative binding energy implies an unbound system.
(c) This assumption that it is two bound neutrons is incorrect.
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
define infection ,prevention and control
Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life