SITI NORHAYATI MOHD MOKHTARCHAPTER 6 : NUCLEAR ENERGY

RADIOACTIVE SUBSTANCE : Substances which contain unstable nuclei

Types of radioactive radiations

Characteristics Types of radioactive radiations

Alpha rays Beta rays Gamma raysType of particleChargeSpeed of movementPenetration powerCan be stopped byDeflection in electric field

Proses R :

Penetration power of alpha , beta and gamma radiations

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Deflection of radioactive rays in an electrical field

Uses of radiactive subtances

: study the age of artifacts / fossils : to kill

cancer cells : to treat thyroid gland diseases

: to detect the leakage of underground pipe

: to study the absorption of fertilisers by plants

: to generate electrical energy in nuclear reactor

Exercise

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The diagram shows the three types of radiation P, Q and R which emitted from a radioactive source.

(a) Name the three types of radiation P, Q and R.

P : ………………………….. Q : ……………………….. R :…………………………

(b) Which type of the radiation above is positively charged? ……………………………………

(c) Arrange the three types of radiations in order of increasing velocity. ………………………

(d) Which type of radiation is not deflected by a magnetic field? …………………………..

3. Fill in the blank on the uses of radioactive substances.

Production of nuclear energy

Nuclear fission Nuclear fusion

LeadAluminiumPaper

(f)Cobalt-60: .………………………………..

…………………………………………….

(g)Uranium-235: …………………………..

……………………………………………..

Medicine

(e)Carbon- 14: ………………………………

…………………………………………….

Archeology

(c) Sodium-24: ………………………………

…………………………………………...

(d) Beta particles: ……………………….

…………………………………………..

Industry

(a)Phosphorus-32: …………………………..

…………………………………………….

(b)Gamma radiation: ………………………

……………………………………………..

Agriculture

Uses of Radioactive Substances

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The splitting of a heavy nucleus into two lighter nuclei

The combining of two ‘light’ nuclei to form a heavier nucleus

NUCLEAR FISSION- A slow moving neutron collides with a uranium nucleus- The neutron is absorbed- The uranium nucleus becomes unstable and split into lighter nucleus- At the same time , a few neutrons will also be released- A lot of energy is released- Neutrons released in single fission can collides again and produce more fission

in a

NUCLEAR FUSION

- Deuterium and tritium ( lighter nuclei ) combined to form a larger unstable nucleus

- The unstable nucleus will break into helium and neutron- A lot of energy is released

Exercise

1. The diagram below shows a nucleus of Uranium-235 being bombarded with particle P. It splits into two smaller nucleus together with the release of three other particles P.

Particle P

Particle P

Particle P

Particle P

The diagram shows a method used to produce nuclear energy.

a) Name the process

b) Where does the process occur naturally?

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(a) Name the process: ………………………………………………………

(b) Name the particle P and atom Q used in the process. ………………………………..

(c) State one beneficial application this process.

…………………………………………………………………………………………………

(d) One of the three particles P released can split other Uranium-235 atoms resulting in a continuous reaction. Name this reaction. ……………………………………………………………………………

The generation of electrical energy from nuclear energy

1) Name reaktor P

2) State the radioactive element that is used in reactor P

Particle P

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3) Name the process which takes place in reactor P

4) Complete the flow chart

5) Name the radiation emitted during the generation of nuclear energy that give adverse effect to the health of living things

Effect or radioactive radiation Destroys body cells Causes cancer Pollutes the environment Cause death Causes mutation Causes abnormalities in foetus Causes sterility

Misuse of radioactive substances Making nuclear weapon Nuclear test destroy the habitats of

living things and pollute the environment

Safety measures while handling radioactive substances

Wear special protective coating Store radioactive substances inthick lead containers or thick concrete slabs

Use Geiger-Muller counter or photographic badges to detect the presence of radioactive rays

Have strict laws to ensure properdisposal of radioactive substances

What are the short term and long term effects of exposure to radioactive radiation to humans?

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(a) Short term effects:i.ii.

(b) Long term effects:i.ii.

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