Notesch # 18

Chapter # 18

Atomic and nuclear Physics Q#1: Choose the correct answer of the statement from the given choices I.

The total number of Protons and the Neutrons present in the nucleus of an atom is called (a) Charge Number (b) Mass Number (c) Neutron Number (d) Proton Number

II.

The total number of Protons or Electrons present in an atom is called (a) Charge Number (b) Mass Number (c) Neutron Number (d) Proton Number

III.

The total number of Protons and Neutrons present in the nucleus of an atom is Represented by (a) X (b) A (c) Z (d) N

IV.

The total number of Protons or Electrons present in an atom is represented by (a) X (b) A (c) Z (d) N

V.

The Elements whose charge numbers are same but mass numbers are different are called (a) Isotope (b) Isomers (c) Isobars (d) None of these

VI.

French scientist ___________ was discovered Radioactivity (a) Henry Becquerel (b) Madam Curie (c) Einstein (d) Nile Bohar

VII.

Speed of alpha rays is ____________ beta rays (a) less (b) greater (c) less than or equal to (d) equal to

VIII.

The speed of ____________ rays is nearly equal to the speed of light

(a) alpha (b) beta (c) gamma (d) X-rays IX.

The mass of a radioactive element remains _____________ after three successive half lives (a) 1/6 (b) 1/8 (c) 1/9 (d) 1/12

X.

Nuclides with mass number greater than __________ are not stable nuclides (a) 83 (b) 82 (c) 85 (d) 81

XI.

E=mc2 is the equation of mass and energy was derived by ___________ (a) Henry Becquerel (b) Madam Curie (c) Einstein (d) Nile Bohar

XII.

If a mass of 20 Kg converted into energy than the amount of energy released is (a) 6.0X 1018J (b) 6 X1020 J (c) 1.8X 1020 J (d) 1.8 X1018 J

XIII.

Breaking of a heavy nucleus into two lighter nuclei releasing huge amount of energy is called (a) Fusion (b) Fission (c) Radioactivity (d) distribution of mass

XIV.

A reaction in which a few small nuclei diffuse to form a heavy nuclei is called (a) Fusion (b) Fission (c) Radioactivity (d) distribution of mass

XV.

The time during which the mass/number of radioactive elements reduce to one half is called (a) Slandered life (b) total life (c) mean life (d) half life

XVI.

The time during which the __________ of radioactive elements reduce to one half is called its half life (a) Number of atoms (b) Mass (c) charge (d) electron

XVII.

The radioactive ray which have zero charge is called __________ (a) alpha rays (b) beta rays (c) gamma rays (d) X-rays

XVIII.

An alpha ray passing through any gas produce ___________ in it (a) Vaporization (b) Excitation (c) polarization (d) Ionization

XIX.

Electron is _________ times lighter than proton.

(a) 1636 (b) 1838 (c) 1836 (d) 1638 XX.

The mass of an electron is ________ (a) 6.6X10-27 (b) 1.67X10-19 (c) 1.6X10-11 (d) 6.6X10-34

XXI.

An element is normally represented symbolically as (a)

XXII.

A Z

X (b)

Z A

X (c) AXZ(d) ZXA

The elements with charge number less than 82 could be made radioactive by bombardment of (a) Proton (b) Electron (c) Neutron (d) Alpha particle

XXIII.

Radioactive rays couldn’t pass through (a) Glass (b) Iron (c) Lead (d) Paper

XXIV.

Radioactive rays normally cause ____________ diseases in human (a) Incurable (b) Curable (c) infectious (d) swear

XXV.

Fission is a __________ process. (a) Exothermal (b) Endothermic (c) Radioactive (d) Chemical

Q#2: Give short answer of the following questions I.

Define atomic structure?

Ans: The atom of an element consists of two parts one is its central part called nucleus and the other is its outer part called electron revolving about the central nucleus. II.

Write down the distribution of charge in an atom?

Ans: The charge of an atom is equally distributed between both parts of atom as all positive charge is possessed by central part (nucleus) and the negative charge is by outer part (electron) revolving around the nucleus. III.

Write down the distribution of mass of an atom?

Ans: The mass of an atom is not equally distributed, but it is more than 99% is possessed by the central part (nucleus) and less than 1% is by outer part (electron) revolving around nucleus. IV.

What is the mass of a Proton and that of a Neutron?

Ans: The mass of the Proton of an atom is 1.67X10-27 Kg, and the Neutron has nearly equal mass. V.

Define atomic mass number ?

Ans: The total number of Protons and Neutrons present in the nucleus of an atom is called atomic mass number and it is normally represented by Z. VI.

Define atomic mass number ?

Ans: The total number of Protons or Electrons present in an atom is called atomic charge number and it is normally represented by A. VII.

How to represent an atom symbolically?

Ans: As we know that the atomic mass and charge numbers are represented by Z and A respectively so an atom could be represented as AZX.

VIII.

Define an Isotope?

Ans: Those elements whose atomic /charge numbers are same but their mass number are different are called isotope. IX.

Define Radioactivity and also explain its different types?

Ans: The process during which an element, with atomic charge number greater than 82 naturally and with atomic number less than 82 artificially, split in to another group of elements with the emission of some sort of radiations in the form of rays and energy is called radioactivity. There are two basic types of radioactivity i.e. (a) Natural Radioactivity (b) Artificial Radioactivity X.

Define Natural Radioactivity?

Ans: The process during which an element with atomic charge number greater than 82 naturally split in to another group of elements with the emission of some sort of radiations in the form of rays and energy is called Natural Radioactivity. XI.

Define Artificial Radioactivity?

Ans: The process during which an element with atomic number less than 82 artificially (with the bombardment of neutron) split in to another group of elements with the emission of some sort of radiations in the form of rays and energy is called Artificial Radioactivity. XII.

Define Radioactive Isotopes?

Ans: The Radioactive elements whose atomic number/ atomic charge number are same but have different atomic mass number are called radioactive Isotopes. XIII.

Who was discovered the Natural Radioactivity?

Ans: In 1896 a French scientist Henry Becquerel discovered natural radioactivity accidently. XIV.

How many types of radiations/rays emitting from a radioactive element during radioactivity?

Ans: During Radioactivity three different types of radiations/rays emitting from a Radioactive element. XV.

Name the different types of Radiations emitting from a radioactive element?

Ans: During Radioactivity three different types of rays emit from a radioactive element those are named as (a) Alpha rays (b) Beta rays (c) Gamma rays.

XVI. Ans:

Explain the nature of each of the rays emitting from a radioactive element?

The alpha rays are positively charged and the beta rays are negatively charged while the gamma rays are neutral. XVII.

Which property do all of the radiations have?

Ans: All of the radiations produce ionization in the gases when they pass through them. And all of the rays effect the photo-graphic plate. XVIII.

Which radioactive rays have higher speed than the other?

Ans: From the properties of radioactive rays it is clear that Beta rays have a higher speed as compare to Alpha rays and also gamma rays have higher speed as compare to he Beta rays.

XIX.

Which type of radioactive rays has the highest speed?

Ans: It is clear from the properties of radioactive rays that Gamma rays have the highest speed as compare to both other types. XX.

What is the highest speed of radioactive rays and which rays have that?

Ans: The highest speed of radioactive rays is nearly equal to the speed of light and Gamma rays have that speed. XXI.

Define half life of a radioactive element?

Ans: The time period during which the amount mass of a radioactive element reduce to one half of its original mass, naturally, is called half life of that element. XXII.

What do you mean by Parent and daughter elements?

Ans: The radioactive element which is passing through the process of radioactivity is called the parent element while the elements produced after the radioactivity and are not radioactive are called daughter elements of the process. XXIII.

Define the stable and unstable Nuclides?

Ans: The nuclei whose atomic charge number is from 1 to 82 are stable nuclides (because they could not precede radioactivity until they are forced to do so by different means), While the nuclei whose atomic charge number is greater than 82 are naturally radioactive and called unstable nuclides.

XXIV.

Can we change a stable nuclide into an unstable nuclide? If yes! Than how can we did so?

Ans: yes! A radioactive element could be changed into an unstable nuclide by the bombardment of neutron. (such elements are also called radioactive isotopes). XXV.

Write down the fields of applications of Radio Isotopes?

Ans: The Radio isotopes are commonly used in the following field of life. (a)Agriculture (b) Medicine (c) Radioactive Dating XXVI. Ans:

Who discovered the mass energy equation?

In 1905 Einstein derived the mass energy relation.

XXVII. Ans:

What is the explanation of the mass energy relation?

This Relation shows that energy and mass are mutually interchangeable.

XXVIII.

Define the theory of mass energy equation?

Ans: This equation states that if a mass ‘m’ of matter moves with the speed of light ‘c’ then it will be converted into energy ’E’ . XXIX. Ans:

What would be the mass of element from which an amount of 1.8 X 1018 J has been released?

As we have E=1.8 X 1018 J C=3 X 108 m/s M=? And by the mass energy equation we have E=mc2 Than we will get m=20Kg. XXX.

Ans:

92

Express the fission reaction in terms of single equation?

235

XXXI.

U+

1 0

n ----------------

141 56

Ba +

36

92

Kr + 301n + . E

Define fission reaction in words?

Ans: The breaking of a nucleus into two parts with the release of large amount of energy is called fission reaction.

OR A radioactive process in which parent nuclide break into two different daughter nuclides due to radioactivity is called fission. XXXII.

Define the controlled fission reaction?

Ans: A system in which the fission reaction is controlled for peaceful purposes is called controlled fission reaction, while the reverse of controlled fission reaction is an atomic bomb. XXXIII.

Define Chain Reaction?

Ans: XXXIV.

How can we control the fission chain reaction?

Ans: To control the fission chain reaction surplus neutrons are absorbed by the Boron OR Cadmium rods. This is only happen in the nuclear reactor.

XXXV. Ans:

Define the nuclear reactor?

.

XXXVI.

On the principle of which reaction atomic bomb works?

Ans: The atomic bomb works on the principle of fission chain reaction, but in this case chain reaction is not controlled by any mean. XXXVII.

In atomic bomb what is the source of destruction?

Ans: In the atomic bomb the source of destruction is the energy released during the chain reaction. XXXVIII.

Define fusion reaction?

Ans: A process in which the lighter nuclei diffuse to form a heavier nuclide is called fusion reaction. XXXIX. Ans:

3 1

H

XL. Ans:

Explain the fusion reaction in terms of a single equation? +

3 1

H ----------------

2

4

He +

1 0

n+

E

What is the origin of released energy in the fusion reaction?

The energy released in the fusion reaction is actually the mass defect in the parent and daughter nuclides.

XLI. Ans:

What is the origin of released energy in the fission reaction?

The energy released in the fission reaction is actually the mass defect in the parent and daughter nuclides. XLII.

How can we evaluate the amount of energy released during the nuclear reaction?

Ans: We can easily evaluate the amount of energy released during any of the nuclear reaction by the Einstein’s mass energy relation. i.e. E= mc2 . where m represents the mass defect in the parent and daughter nuclides. XLIII.

Where nuclear fusion does happening in the universe?

Ans: The nuclear fusion reaction is always happening in the universe on the core of the sun and on other stars. XLIV.

How many products are there of the fusion of four hydrogen nuclides?

Ans: There are following fusion products of four Hydrogen nuclides are as, (a) Helium nuclide (b) Two Positron (c) Three Alpha-rays (d) nearly 25.7MeV of energy.

XLV. Ans:

Which reaction is the responsible for the solar and staler energy?

Fusion Reaction is the responsible for the solar and stellar energy. XLVI.

Why is it difficult to control the radioactive Hazards?

Ans: Because these radiations are not visible and their adverse effect also not appear at once. XLVII.

How do nuclear radiations affect the human body?

Ans: The cells of human body are destroyed due to the ionization property of the radioactive radiations and destroy the health tissues as well. XLVIII. Ans:

Whether the diseases caused by nuclear radiation are curable or not?

No! the diseases caused by the nuclear radiation are incurable. XLIX.

How can we protect our selves from nuclear radiations?

Ans: There are a number of precautions to protect ourselves from the incurable effects of nuclear radiation, but some of them are as under We should use instruments which can detect these radiations so that we will stay away from them, we should have to use lead around the radioactive element, diagnose ourselves regularly for the nuclear radiations.

Long Questions Q#3: Write a note on the half life of a radioactive element? Q#4: Explain the radioactivity its types and how was it discovered. Q#5: Prove with the help of an experiment that the nuclear radiations are of three types? OR Study the nature of nuclear radiations emitting from a radioactive material, by an experiment. Q#6: write down the properties of alpha/beta/gamma rays?

Q#7: (a) Explain the nuclear fission reaction and fission chain reaction? (b)Discuss the different methods of controlling chain reaction and its applications. Q#8: (a) Write a comprehensive note on the fusion reaction? (b) write a comprehensive note on Einstein’s mass energy equation. Q#9: Explain the different methods to minimize nuclear radiation hazards.