Nuclear Physics Book Back Questions 10th Science Lesson 6

10th Science Lesson 6

6] Nuclear Physics

Book Back Questions with Answer and Do You Know Box Content

Do You Know?

There have been 29 radioactive substances discovered so far. Most of them are rare earth metals and transition metals.

Uranium, named after the planet Uranus, was discovered by Martin Klaproth, a German chemist in a mineral called pitchblende.

Electron Volt (eV) is the unit used in nuclear physics to measure the energy of small particles. It is nothing but the energy of one electron when it is accelerated using an electric potential of one volt.

1 eV = 1.602 x 10^-19 joule.

1 million electron volt = 1 MeV = 10⁶ eV (mega electron volt)

The energy released in a nuclear fission process is about 200 MeV.

Nuclear fusion is the combination of two lighter nuclei. The charge of both nuclei is positive. According to electrostatic theory, when they come closer they tend to repel each other. This repulsive force will be overcome by the kinetic energy of the nuclei at higher temperature of the order of 10⁷ to 10⁹ K.

The nuclear bomb that was dropped in Hiroshima during World War II was called as ‘Little boy’. It was a gun-typed bomb which used a uranium core. The bomb, which was subsequently dropped over Nagasaki was called as ‘Fat man’. It was an explosion type bomb, which used a plutonium core.

Sun fuses about 620 million metric tons radiates about 3.8 x 10²⁶ joule of energy per second. When this energy is radiated towards the Earth, it decreases in its intensity. When it reaches the Earth its value is about 1.4 kilo joule per unit area in unit time.

How old is our mother Earth? Any guess?? It is nearly 4.54 x 10⁹ years (around 45 Crore 40 lakh years). Wow!!

Dosimeter is a device used to detect the levels of exposure to an ionizing radiation. It is frequently used in the environments where exposure to radiation may occurs such as nuclear power plants and medical imaging facilities. Pocket dosimeter is used to provide the wearer with an immediate reading of his/her exposure to X-rays and γ rays.

Choose the best answers:

1. Man – made radioactivity is also known as _____________

(a) Induced radioactivity

(b) Spontaneous radioactivity

(c) Artificial radioactivity

(d) a & c

2. Unit of radioactivity is ________________

(a) Roentgen

(b) Cuie

(c) Becquerel

(d) All the above

3. Artificial radioactivity was discovered by ______________________

(a) Bequerel

(b) Irene Curie

(c) Roentgen

(d) Neils Bohr

4. In which of the following, no change in mass number of the daughter nuclei takes place

i) α decay ii) β decay iii) γ decay iv) Neutron decay

(a) (i) is correct

(b) (ii) and (iii) are correct

(c) (i) & (iv) are correct

(d) (ii) & (iv) are correct

5. ______________ isotope is used for the treatment of cancer.

(a) Radio Iodine

(b) Radio Cobalt

(c) Radio Carbon

(d) Nickel

6. Gamma radiations are dangerous because

(a) It affects eyes & bones

(b) it affects tissues

(c) It produces genetic disorder

(d) It produces enormous amount of heat

7. ________________ aprons are used to protect us from gamma radiations.

(a) Lead oxide

(b) Iron

(c) Lead

(d) Aluminium

8. Which of the following statements is/are correct?

i. α particles are photons

ii. Penetrating power of γ radiation is very low

iii. Ionization power is maximum for α rays

iv. Penetrating power of γ radiation is very high

(a) (i) & (ii) are correct

(b) (ii) & (iii) are correct

(c) (iv) only correct

(d) (iii) & (iv) are correct

9. Proton – Proton chain reaction is an example of _________________

(a) Nuclear fission

(b) α – decay

(c) Nuclear fusion

(d) β – decay

10. In the nuclear reaction ₆X¹² _ZY^A, the value of A & Z.

(a) 8, 6

(b) 8, 4

(c) 4, 8

(d) Cannot be determined with the given data

11. Kamini reactor is located at _________________

(a) Kalpakkam

(b) Koodankulam

(c) Mumbai

(d) Rajasthan

12. Which of the following is/are correct?

i. Chain reaction takes place in a nuclear reactor and an atomic bomb.

ii. The chain reaction in a nuclear reactor is controlled.

iii. The chain reaction in a nuclear reactor is not controlled.

iv. No chain reaction takes place in an atom bomb.

Fill in the blanks:

1. One roentgen is equal to ________________ disintegrations per second.

a) 3.7 x 10⁹

b) 3.7 x 10¹⁰

c) 3.7 x 10¹¹

d) 3.7 x 10¹²

2. Positron is an ___________________

1. Anti particle of electron
2. Anti particle of neutron
3. Anti particle of proton
4. None of the above

3. Anaemia can be cured by _________________ isotope.

1. Radio Cobalt
2. Radio Sodium
3. Radio Iron
4. None of the above

4. Abbreviation of ICRP ______________.

1. International Commission on Radiological Prevention.
2. International Convention on Radiological Prevention.
3. International Convention on Radiological Protection.
4. International Commission on Radiological Protection.

5. ___________________ is used to measure exposure rate of radiation in humans.

1. Roentgen
2. Becqurel
3. Curie
4. All the above

6. ______________ has the greatest penetration power.

1. Alpha rays
2. Beta rays
3. Gamma rays
4. Delta rays

7. _ZY^A🡪_Z+1Y^A + X; Then, X is ______________.

1. _-1e⁰
2. _-2e⁰
3. _-3e⁰
4. _-4e⁰

8. _ZX^A🡪_ZY^A This reaction is possible in _______________ decay.

1. Beta
2. Alpha
3. Delta
4. Gamma

9. The average energy released in each fusion reaction is about _________________ J.

1. 3.86 × 10^-12
2. 3.86 × 10^-24
3. 3.84 × 10^-24
4. 3.84 × 10^-12

10. Nuclear fusion is possible only at an extremely high temperature of the order of _____________ K.

1. 10⁷ to 10⁹
2. 10⁷ to 10¹⁰
3. 10⁷ to 10¹¹
4. All the above

11. The radio isotope of ___________ helps to increase the productivity of crops.

1. Sodium
2. Iron
3. Phosphorus
4. Iodine

12. If the radiation exposure is 100 R, it may cause __________________.

1. Skin disease
2. Lung disease
3. Fatal disease
4. Heart disease

State true or false. If false, correct the statement:

1. Plutonium – 239 is a fissionable material.

2. Elements having atomic number greater than 83 can undergo nuclear fusion.

3. Nuclear fusion is more dangerous than nuclear fission.

4. Natural uranium U – 238 is the core fuel used in a nuclear reactor.

5. If a moderator is not present, then a nuclear reactor will behave as an atom bomb.

6. During one nuclear fission on an average, 2 to 3 neutrons are produced.

7. Einstein’s theory of mass energy equivalence is used in nuclear fission and fusion.

Match the following:

Match: I

a. BARC – Kalpakkam

b. India’s first atomic power station – Apsara

c. IGCAR – Mumbai

d. First nuclear reactor in India – Tarapur

Match: II

a. Fuel – lead

b. Moderate – heavy water

c. Control rods – cadmium rods

d. Shield – uranium

Match: III

a. Soddy Fajan – Natural radioactivity

b. Irene Curie – Displacement law

c. Henry Bequerel – Mass energy equivalence

d. Albert Einstein – Artificial Radioactivity

Match IV:

a. Uncontrolled fission reaction – hydrogen bomb

b. Fertile material – nuclear reactor

c. Controlled fission reaction – breeder reactor

d. Fusion reaction – atom bomb

Match: V

a. Co – 60 – Age of fossil

b. I – 131 – Function of heart

c. Na – 24 – Leukemia

d. C – 14 – Thyroid disease

Arrange the following in the correct sequence:

1. Arrange in descending order, on the basis of their penetration power:

Alpha rays, beta rays, gamma rays, cosmic rays

2. Arrange the following in the chronological order of discovery:

Nuclear reactor, radioactivity, artificial radioactivity, discovery of radium

Complete the analogy:

1. Spontaneous process: Natural Radioactivity, Induced process: _____________

2. Nuclear Fusion: Extreme temperature, Nuclear Fission: _____________

3. Increasing crops: Radio phosphorus, Effective functioning of heart: _______________

4. Deflected by electric field: α ray, Null Deflection: _________________

Consider the statements given below and choose the correct option:

Mark the correct choice as:

(a) If both assertion and reason are true and reason is the correct explanation of assertion

(b) If both assertion and reason are true but reason is not the correct explanation of assertion

(c) If assertion is true but reason is false

(d) If assertion is false but reason is true

1. Assertion: A neutron impinging on U²³⁵, splits it to produce Barium and Krypton.

Reason: U – 235 is a fissile material.

2. Assertion: In a β – decay, the neutron number decreases by one.

Reason: In β – decay atomic number increases by one.

3. Assertion: Extreme temperature is necessary to execute nuclear fusion.

Reason: In a nuclear fusion, the nuclei of the reactants combine releasing high energy.

4. Assertion: Control rods are known as ‘neutron seeking rods’.

Reason: Control rods are used to perform sustained nuclear fission reaction.

Answers:

Choose the best answer:

1.a & c 2. All the above 3. Irene Curie 4. (ii) and (iii) are correct 5. Radio Cobalt

1. it produces genetic disorders 7. Lead

8. (iii) and (iv) are correct 9. Nuclear Fusion 10.

1. 4,8 11. Kalpakkam 12. (i) and (ii) are correct

Fill in the blanks:

1.3.7 X 10¹⁰ 2. Anti particle of electron 3. Radio Iron 4.

1. International Commission on Radiological Protection 5. Roentgen

6. Gamma rays 7.

1. _-1e⁰ 8. Gamma decay 9. 3.84 × 10^-12 10. 10⁷ to 10⁹

True or False:

1.True

2.False (Elements having an atomic number greater than 83 can undergo nuclear fission not fusion)

3.False (Nuclear fission is more dangerous than nuclear fusion)

4.False (U-238 is not a fissile material Only fissile materials are used in the fuel of a nuclear reactor)

5.True

6.True

7.True

Match: I

1. Mumbai
2. Tarapur
3. Kalpakkam
4. Apsara

Match: II

1. Uranium
2. Graphite
3. heavy water
4. lead

Match: III

1. Displacement law
2. Artificial Radioactivity
3. Natural radioactivity
4. Mass energy equivalence

Match: IV

1. Atom bomb
2. Breeder reactor
3. Nuclear Reactor
4. Hydrogen Bomb

Match: III

1. Leukemia
2. Thyroid disease
3. Function of Heart
4. Age of fossil

Arrange the following in correct sequence:

1.Gamma rays, Beta rays, Alpha rays, Cosmic rays.

2. Radioactivity (1896), Discovery of radium (1898), Artificial radioactivity (1934), Nuclear reactor (1942).

Complete the analogy:

1. Artificial Radioactivity
2. Room Temperature
3. Radio Sodium
4. Gamma Ray

Reason and Assertion:

1. Both assertion and reason are true and reason is the correct explanation of assertion
2. Assertion is false but reason is true.
3. Both assertion and reason are true and reason is the correct explanation of assertion
4. Both assertion and reason are true and reason is the correct explanation of assertion