Nuclear Chemist Interview Questions And Answers

These rays are similar to electromagnetic radiation and possess very short wavelength. The daughter nucleus formed generally exists in the excited state. While returning to the ground state they generally emit its excess energy as γ-ray photon. Here the atomic number and the mass number of the daughter nucleus remains the same as of the parent nucleus.

In the radioactive decay the mass of the parent nucleus is usually greater than that of the daughter nucleus and hence in radioactive decay loss of mass occurs. According to Einstein’s equation the lost mass appears as an energy which is shared between the emitted particle and the daughter nucleus.

☛ a. Zeroth law: If any two systems are in thermal equilibrium with the third system, then they are also in thermal equilibrium with each other.
☛ b. First law: First law of thermodynamic states that energy can neither be created nor be destroyed but it can only be converted from one form to another.
☛ c. Second law: This law states that “all processes in nature tend to occur with an increase in entropy and the direction of change always lead to the increase in entropy.”
☛ d. Third law: This law states that “The entropy of a perfect crystal of each element and a compound is zero at absolute zero.”

According to this principle, In the ground state of an atom the electrons are added one by one to the various orbitals in order of their increasing energy starting with the orbitals of lowest energy. The order of increasing energies of various orbitals can be calculated by the (n+1) rule. However if the (n+1) value of two different orbitals are same then the orbitals with lower value of n has lower energy.

It is denoted by m. This quantum number explains us that when a source producing spectral lines are placed in a magnetic field, then each spectral line splits up into number of lines. This is also known as Zeeman Effect.

In order to calculate the pH of a solution you have to use the formula pH= -log [H+] or pH = -log [H3O+]

The main useful isotope, and the one that has become controversial for reasons I'm not sure I totally understand, is plutonium.

Well, the natural radiation is mainly cosmic rays interacting with the earth's atmosphere, and we get a good bit of radiation on the earth's surface. The closer you are to the cosmos, the more radiation you get. So that if you're up in an airplane, you'll get considerably more than on the Earth's surface. Or people living at 5,000 feet, as I do, will get more than people living at sea level. But it's a part of the human environment just as air is, or anything else. It's most unremarkable.

Well, the worst that can happen in a modern nuclear plant is not even a fire. And it certainly isn't an explosion. It can't blow up like a weapon. It just can't. If I could make a comparison, your yule log in your fireplace versus gunpowder. I mean, you cannot blow up a nuclear plant like you can assemble uranium in a weapon to give you a tremendous explosion. It's just cannot happen. And those people that suggest that it can aren't doing the public much of a service.

The skin on your hand is probably sufficient to stop most of it.

Iron ore is consists of Fe2O3

Fat found in human body is mainly composed of

☛ Glycerides
☛ Glycerides+Phospholipids
☛ Glycolipids
☛ Phosphoinotisides
☛ Tocopherol

Mole is the unit used to define the number of chemical substance present in a substance. It is the amount of substance which consists of the same number of chemical units as there are atoms in exactly 12 gram of pure carbon-12.

The electron not only spins around the nucleus but also about its own axis. The direction of electron spin is clockwise or anti-clockwise. This quantum number helps to explain the magnetic properties of the substance.

Quantum numbers are defined as a set of four numbers with the help of which we can get complete information about all the electrons in an atom. Thus with the help of these numbers we can get the information about the energy, location, type of orbital occupied, shape of that orbital etc. Mainly there are four types of quantum numbers. They are:

☛ a. Principal Quantum Number: It is denoted by n. It tells us about the energy level or shell in which the electron is present. The value of n can be 1,2,3,4…….etc. but it cannot be zero. It gives us the information about the average distance of electrons from the nucleus, determines the energy of electron in hydrogen atom and hydrogen like atoms. It also gives us the information about the maximum number of electrons that a shell can have by using the formula 2n2.

☛ b. Azimuthal Quantum Number: It is denoted by l. Through this quantum number we get to know the number of sub-shells present in the main shell. It also gives information about the shapes of various shells present within the same principal shell and also about the relative energies associated with these sub-shells.

☛ c. Magnetic Quantum Number: It is denoted by m. This quantum number explains us that when a source producing spectral lines are placed in a magnetic field, then each spectral line splits up into number of lines. This is also known as Zeeman Effect.

☛ d. Spin Quantum Number: The electron not only spins around the nucleus but also about its own axis. The direction of electron spin is clockwise or anti-clockwise. This quantum number helps to explain the magnetic properties of the substance.

A system that can neither exchange matter nor heat with the surrounding is known as an isolated system. For example: Water placed in a vessel that is closed as well as insulated.

α – particles are more massive than the β – particles. The a- particles generally travel in a straight line and on collision with gas molecules they are not scattered. The β- particles follow a zigzag path and on collision with gas molecules they are scattered.

These are the nuclei that belong to the same element and have the same number of protons. They occupy the same position in the periodic table and hence have the same atomic number. The isotopes of given element contains same number of electrons and hence have the same chemical properties, thus it is difficult to separate them from one another using chemical methods. However the Isotopes of given element differ in mass dependent physical properties like rate of diffusion and thus can be separated from one another using physical properties.

These are the nuclei of the neighbouring group having the same mass number but different atomic number. The isobaric nuclei belong to the different group and hence occupy different positions in the periodic table. They also differ in their chemical properties.

☛ A nuclear reaction is different from a chemical reaction.
☛ In a chemical reaction, atoms of the reactants combine by a rearrangement of extra nuclear electrons but the nuclei of the atoms remain unchanged.
☛ In a nuclear reaction, however, it is the nucleus of the atom which is involved.
☛ The number of protons or neutrons in the nucleus changes to form a new element itself.
"A study of the nuclear changes in atoms is termed as Nuclear chemistry".

C14 dating technique is usually used to find the age of dead organism. In this technique generally the concentration ratio of C14 to C12 is used in order to determine ages upto 20,000 years. This is widely used in archaeology. C14 has a half-life period of 5700 years. When an organism dies the C14 content in them begins to decay with its characteristic to the half-life period. The concentration of C14 / C12 decreases and this decrease from the equilibrium is used as a measure of the age of the sample.

C14 emits α β ray of low energy. In living samples , special counters with low background are used as the activity due to C14 is low in them.

These rays consist of electrons. When the conversion of a neutron into proton takes place then an electron is ejected out, along with electron another particle is also ejected out which is known as anti-neutron. The mass of this anti-neutron in negligible. When a β ray is emitted by the parent element then the atomic number of the daughter is more by one unit than the parent element. However the mass number of both remains the same.

These are the nuclei that contain same number of neutrons but they differ in the number of protons and also in the mass number.

Dyes like fluorescein, rose Bengal are absorbed by cancerous cells, thus in order to locate the brain tumour location the dye labelled with I131 is given to the patient. Then the entire space around the skull is scanned by the help of special counters and the place where ever I131 is accumulated is found and thus it is possible to locate the brain tumour to some extent.

The energy associated with α and β particles are sufficient to break the bonds in the molecules of the medium which lead to the formation of free radicals. These free radicals initiate various chemical reactions. The passage of α and β particles also produce some physical changes.