Nuclear Energy–10th Science Learning Cards

Chapter-10

Nuclear Energy

Learning Card-1

Choose the correct answer:

1. Fuel used in Nuclear reactor is

a) Carbon b) Uranium c) Cadmium d) Graphite.

2. Which are of the following materials is commonly used as moderation in a nuclear reactor

a) Cadmium b) Boron c) Graphite d) Liquid Sodium

3. Heavy water is used in a nuclear reactor to :

a) Produce the neutrons b) Slow down the neutrons

c) Accelerate the neutrons d) Absorb the neutrons

Answer the following Questions:

1. Define Nuclear fission

The Process by which heavy nucleus split into lighter 2 nuclei with liberation of large amount of energy is called ‘Nuclear fission.

2. Which metal is used to make control rods?

Cadmium

3. Where nuclear fusion do occurs naturally?

Sun and stars

4. Define Uranium Enrichment.

Naturally occurring uranium contains about 0.7% of ₉₂U²³⁵ isotope which is fissionable. Self-sustained chain reactions are not possible in natural uranium which is mostly made up of isotope ₉₂U²³⁸. To make it fissionable ₉₂U²³⁵ content of the ore is to be enriched by separating 92U235 and ₉₂U²³⁸ isotopes. This process is known as enrichment of uranium.

5. Write Einstein’s Energy mass relation equation and name the components of relation.

E = mC2

E = Energy released in joules

m= mass transformed in kilograms

C = Velocity of light 3x108 ms-1

6. Draw the schematic diagram of fission chain reaction of ₉₂U²³⁵ isotope.

7. Write two differences between nuclear fission and nuclear fusion.

Nuclear fission	Nuclear fusion
1. A heavy nucleus is split into two lighter nuclei with liberation of energy 2. Can be controlled 3. Not require high temperature	1. Two or more lighter nuclei fuse to form a heavy nucleus, with liberation of energy. 2. no mechanism to control 3. Requires extremely high temperature.

Chapter-10

Nuclear Energy

Learning Card-2

Choose the correct answer

1. The minimum size of the fissionable material required to sustain chain reaction is called.

a) Mass defect b) Critical size c) Optimal size d) chain size

2. Transmutation means.

a) Conversion of atomic number of an atom.

b) Conversion of charge number of an atom.

c) Mass and energy are inter convertible

d) Creation of neutrons by fission.

3. Which one of the following material suited for fission?

a) Uranium 238 b) Naturally occurring uranium

c) Radium - 226 d) Enriched Uranium 235

Question and Answers:-

1. What is meant by chain reaction?

“A chain reaction is that process in which number of neutrons keep on multiplying after each fission rapidly in geometric progression, till the whole of the fissionable material is disintegrated”

2. Write the equation of nuclear fission ₉₂U²³⁵ bombarded with neutron

₉₂U²³⁵ + ₀n¹ -----> ₅₆Ba¹⁴² + ₃₆Kr⁹¹ + 3 ₀n¹ + energy

3. Name the reactor which is used to prepare radio isotopes.

Breeder Reactor

4. In Karnataka, where the nuclear power plant situated?

Kaiga.

5. What is nuclear fusion? Give an Example.

Two or more lighter nuclei fuse to form a heavy nucleus with the liberation of energy is called Nuclear fusion.

Example ₁H² + ₁H² ----> ₂He⁴ + Energy

6. Draw a neat diagram of nuclear reactor and label it.

7. Schematically represent chain reaction.

Chapter-10

Nuclear Energy

Learning Card-3

Choose the correct answer

1. Fusion reaction take place at high temperature because.

a) Atomic are ionized at high temperature.

b) Nuclei of atom break at high temperature.

c) Nuclei of atom break at high temperature

d) High temperature helps to overcome repulsion between nuclei.

2. Exposure to high frequency ultraviolet light may cause.

a) Premature cataract. b) Skin cancer. c) Skin burns d) All of the above.

3. Nuclear power reactor works on the principle of?

a) Exothermic reaction b) endothermic reaction

c) Controlled nuclear fission d) Thermo nuclear fusion

Question and Answers

1. Write Einstein’s mass-energy relation equation.

E = mc2

2. What is unclear reactor?

The device used to carry out the fission under controlled condition is called a nuclear reactor.

3. Where do nuclear fusion reactions occur naturally?

Sun and stars

4. Write the functions of the following. a) Uranium 235 b) Cadmium rods

a) Uranium 235 - Nuclear fuel

b) Cadmium rod - absorb neutrons

5. Calculate the energy in Joules. When 1 amu of mass gets converted into energy.

1 a.m.u = 1.66 x 10-27 Kg

E = mc2

E=1.66 x 10-27 x 3 x 108 x 3 x 108

E=14.98 x 1011 Joules

6. Write any three difference between nuclear fission and nuclear fusion.

Nuclear Fission	Nuclear Fission
1. A heavy nucleus is split into two lighter nuclei. 2. Can be controlled 3. Not require high temperature.	1. Two or more lighter nuclei fuse to form a heavy nucleus. 2. No mechanism to control. 3. Require high temperature.

7. State the precautions to be taken which handling nuclear reaction materials?

a) The radioactive matter is impregnated in glass slab and disposed in the deep sea in strong steel, containers.

b) Lead jackets are worn by the workers of nuclear power stations.

c) Nuclear waste is buried very deep underground.

8. Differentiate between chemical reaction and nuclear reactions

Chemical reactions	Nuclear reactions
1. Valence electrons of the atoms participate in the re- action. 2. Nuclear of an atom does not undergo any change 3. Products are predictable 4. Mass in conserved	1. Electors of an atom have no role to play in nuclear reactions. 2. Nuclear of the atoms undergo a change. 3. Products depend upon conditions 4. Mass is converted into energy.

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