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NUCLEAR
FUSION-RADIOACTIVITY
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NUCLEAR
FUSION
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"The
process of forming heavy nucleus from two or more light nuclei in
which energy is released is called "NUCLEAR FUSION." |
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OR
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The
combining of two lighter nuclei to form a relatively heavier
nucleus with the release of energy is called "NUCLEAR FUSION." |
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EXAMPLE
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FUSION
OF DEUTERIUM AND TRITIUM
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| When 1H2 and 1H3 nuclei are brought together they form 2He4 nucleus with the release of energy. | ||||
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1H2+1H3
è 2He4+0n1+Energy.
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CHARACTERISTICS
OF FUSION
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| (1)
Energy release during a fusion process in greater than that of fission. (2) To produce a fusion process a very high temperature is required to over come repulsion between positive nuclei. |
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| DEFINE RADIOACTIVITY. WRITE PROPERTIES OF RADIOACTIVE RAYS. | ||||
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RADIOACTIVITY
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| All the elements having atomic number greater than 82 emit invisible radiation all the time. The phenomenon of emission of these powerful rays is called "Natural Radioactivity" and the element that emits such rays is called "Radio Active Element". | ||||
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TYPES
OF RADIO ACTIVE RAYS
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There
are three types of radioactive rays:
a-Rays
b-Rays
g-Rays |
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PROPERTIES
OF a-RAYS
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| (a) NATURE: a - rays consist of α particle. Each α particle consists of Helium(2He4) nucleus. | ||||
| (b) CHARGE: a - particle carry positive charge. | ||||
| (c) MASS: Mass of each a - particle is 4 times that of a proton or H-atom. | ||||
| (d) IONIZATION: Ionization power of a - rays is very high. | ||||
| (e) PENETRATION POWER: Penetration power of a - rays is very small. | ||||
| (f) FLUORESCENCE: a - rays produce fluorescence in different substances. | ||||
| (g) EFFECT ON HUMAN BODY: a - rays produce burn and sore on human body. | ||||
| (h) ARTIFICIAL RADIO ACTIVITY: a - rays can produce artificial radioactivity is certain nuclei. | ||||
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PROPERTIES
OF b-RAYS
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| (a) NATURE: b - rays consist of fast moving electrons. | ||||
| (b) CHARGE: b - rays have negative charge. | ||||
| (c) VELOCITY: Velocity of b - rays is from 9 x 107 m/sec to 27 x 107 m/sec. | ||||
| (d) EFFECT ON PHOTO GRAPHIC PLATE:b - rays affect photo graphic plate. | ||||
| (e) IONIZATION POWER: Ionization power of b - rays is very small. | ||||
| (f) KINETIC ENERGY: Kinetic energy of b - rays is less than that of a - rays. | ||||
| (g) FLUORESCENCE: b - rays produce fluorescence in different substance. | ||||
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PROPERTIES
OF g-RAYS
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| (a) NATURE: g - rays are electromagnetic radiation. | ||||
| (b) CHARGE: g - rays are no charge. | ||||
| (c) VELOCITY: g - rays travel with the velocity of light that is 3 x 108 m/sec. | ||||
| (d) PENETRATION POWER: Penetration power of g - rays is very large. It is about hundred times larger than that of b -rays. | ||||
| (e) FLUORESCENCE: g - rays produce feeble fluorescence When incident on screen coated with barium platino cyanide. | ||||
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