Download - Lesson 10.3 Smktsd Pc01

8/17/2019 Lesson 10.3 Smktsd Pc01

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RadioisotopesRadioisotopes are unstable isotopes which decay andgive out radioactive emissions.Radioisotopes are naturally occurring or artificially

produced.

Uses of radioisotopesThere are many uses for radioisotopes in a widerange of fields including medicine, agriculture,industry and archeology.

(1) MedicineIn medicine field radioisotopes are used in thediagnosis of certain diseases , providesinformation of the specific organs of a patient ortreat disease.

(a) Sodium-!Sodium-! has a half-life "# hours is usedto detect the positions of blood clots(thrombosis) in veins.Sodium-! is in$ected into the bloodstream and gamma rays and beta raysemitted is detected by a ray cameraoutside the body.

(b) Technetium -%%Technetium -%% has a half-life of $ust &

days is used to study the blood in heart.It is a gamma- only emitter and producesno harmful alphas or betas inside the body.The Technetium is combined into samplesof the protein albumin, and this is in$ectedinto the patient. Its movement round thebody can be followed by a gamma raycamera, pic'ing up the gammas emittedfrom the Technetium -%%.

(c) enon-"enon-" has a half-life # days in used in

studying lung function.* patient can be as'ed to breathe aircontaining the gas +enon-" . Thegamma rays emitted are studied using agamma camera which produces a pictureof patients lungs from the gammaradiation each one receives. The patientsoon breathes out all the +enon andreceives only a tiny dose of radiation.

o alpha or beta radiation is produced tocause local internal ionisation damage.

(d) Iodine-""Iodine-"" has a half-life days.It emits gamma rays and used for

detecting changes in the thyroid glands./atients are given an intravenous in$ectionof iodine-"" . * detector is placed nearthe thyroid to read its activity or function.

(e) Iodine-"Iodine-"" has a half-life " hours.It is used to detect bloc'age in the 'idneysof patients.Iodine-" is in$ected into a patient. The 0-1 tube s placed on the patients body totrace the radioactive rays.

(f) Iodine-"#Iodine-"# has a half-life &2 days.It is used to estimate the volume of bloodby in$ecting a measured volume of humanserum albumin (3S*) labelled with asample of iodine-"#.

(g) 4obalt-&24obalt-&2 has a half-life # years.It is widely used to give patient s a largedose of gamma radiation for the treatment

of internal cancers. * restricted beam ofgamma radiation is carefully directed atcancer site from an e+ternal cobalt source.This dangerous source is heavily shieldedand its operated by remote control frombehind thic' lead and concrete walls.4obalt-&2 also is used to sterilise medicale5uipments.

(2) Industry(a) Strontium-%2

Strontium-%2 has a half-life years.

It is used to measure the thic'ness ofpaper in a paper industry . It emits betaradiation. * radioactive source containingstrontium-%2 is placed at one side of thepaper and a detector on the other side.The detector registers a higher count if thepaper is too thin and a lower count if it istoo thic'.

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LESSON 3 -

Understanding the uses of radioisotopes


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(b) Sodium-!Sodium-! has a half-life "# hours is usedto test for lea'age of underground pipes.Sodium-! is added into the water in thestorage tan'. * 0-1 tube is moved abovethe underground pipe , a lea'age can be

detected. The lea'age can be detected when the tube registers a higher reading.

(c) /olonium -"2/olonium -"2 has a half-life "!2 days. Itemits alpha radiation It is used toneutralise static charge in photographicplates or charges on clothes. The alphaparticles ionise the air particles intopositive and negative ions which neutralisethe photographic plates or the clothes.

(d) 4obalt-&24obalt-&2 has a half-life # years. It is usedto chec' welds in steel structures andpipelines 0amma radiation from a largecobalt-&2 source placed on one side of asteel structure e+poses a photographicplate at the other side. * flaw such as abubble or crac' inside a weld on a pipeline

would be visible on the e+posed film.

(e) *mericium-!"*mericium-!" has a half-life !&2 years.

It is used in a smo'e alarm.*mericium-!" emits beta particles whichionise air The air ions will then conductelectricity allowing a small current to flowthrough. 6hen smo'e enters the alarm ,the smo'e particles get in the way of thebeta radiation , reducing the ionisation andthe current across the alarm. This drop incurrent sets off the alarms.

(3) Aricu!ture

(a) /hosphorus-/hosphorus- has a half-life "# days./hosphorus- is used as a tracer in thestudy of the effectiveness of fertili7ers.The plants are watered with a solutioncontaining phosphorus-. * leaf ispluc'ed and tested for radioactivityeveryday for a wee'. If the activity

recorded increases then the plant hasabsorbed phosphorus.

(b) 4obalt-&24obalt-&2 has a half-life # years. Thegamma radiation emits from cobalt-&2 can

be used for food preservation. Somefoodstuffs, li'e grain and dried beans, areoften attac'ed by pests while in store.Radiation treatment 'ill these pests andreduces the losses.The gamma radiation is also used tocontrol insect pests which damage crops.1ale insects are bred in laboratory andthen irradiated. This does not 'ill them butdamages their se+ cells, ma'ing themsterile- unable to produce offspring. Thesemales are then released in great numbers

in affected areas. They breed as usual withnormal females ,but no new generation ofthe insects is hatched. So the pest iscontrolled.

(c) Radioactive radiation also used to inducegenetic mutation in a plant ( change thegenes of plants) in order to produce abetter strain which has a higher resistanceagainst diseases.

(") Arc#eo!oy

(a) 4arbon-"!

4arbon-"! has a half-life # 822 yearsIt is used to measure the age of aarchaeological specimen by carbondating method.9rdinary carbon contains a very smallproportion of carbon-"! , produced whencosmic rays from space collide withnitrogen-"! in atmosphere. :iving plantsta'e up the carbon-"! in the carbon

dio+ide they use for photosynthesis, as doanimals when they eat the plants for food.6hile the plant or animal is alive, theproportion of cabon-"! to ordinary carbon-" in their tissues stays constant, but oncethey die, the carobn-"! begins to decay ;

with a half-life of # 822 years. To date anarcheological specimen , a small sampleof carbon is e+tracted from it.

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(b) atigue(c) ausea(d) 3air loss

(e) :eu'emia(f) 4ataracts(g) Bomiting(h) Infertility in male(i) 9rgan failure($) =eath

() 0enetic effect0enetic effect appear in future generationsof the e+posed person as a result ofradiation damage to reproductive cells@+amples of somatic effects areA

(a) 4hromosome abnormalities

(b) Cirth defects(c) 4ongenital defects

( =own Syndrome, DlinefelterSyndrome and TurnerSyndrome)

(d) /remature death(e) 4ancer in later life

Safety precautions in t#e #and!in of Radioacti%eSu&stances

(") o eating, drin'ing , smo'ing or applying

cosmetics are not allowed where anyradioactive materials are handled.

() =isposable gloves and protective clothingare worn.

() @ye glasses made of lead are used at alltimes when handling radioactive substances.

(!) 1as's are worn in mines where radioactivedust particles are air-borne

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("&) 6or'ers are chec'ed for radiationcontamination by using sensitive radiationmonitors before they leave their place of

wor'.("8) 6hen radioactive material are used in

medicine , the material with a short half-life

is chosen.

Radioacti%e aste Manaeent

Radioactive waste consists of a variety of materialsre5uiring different methods of management to protectpeople and the environment.They are classified as low-level, medium level andhigh-level.(") :ow level wastes

0enerated ? >rom hospitals, nuclear power

stations, research laboratoriesand industries.

@+amples? 4omprises paper, rags tool,clothing, filters, gloves,

wrappers, bioha7ard suit andshoes.

3alf-life ? Short1anagement? Solid wastes are stored in a

closed container and buried inshallow landfill sites(underground).

() 1edium level wastes

0enerated? uclear power stations,research laboratories andindustries.

@+amples? 4omprises resins, chemicalsludge, reactor components.

3alf-life? :ong1anagement? Solidified in concrete or bitumen

and then buried underground

() 3igh level wastes

0enerated? uclear power stations.@+amples?


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0 The diagram shows an arrangement ofapparatus is used in a factory to determine thethic'ness of plastic sheets.

6hich type of radioactive source would be bestfor this deviceE

Radiation 3alf-life

A α " day

* α "2 years

+ β " day

, β "22 years

The diagram shows the process of detecting alea'age in a pipe.

Radioisotope that can be added into the water is

A 4arbon-"!* Iodine-""+ Sodium-!, /hosphorus-

The diagram shows a logic gate system is usedin a factory to ensure the volume of paint incontainers is within the predetermined range.

6hich type of ray is emitted from theradioactive sourceE

A *lpha particle

* Ceta particle+ 0amma ray

The diagram shows the structure of a smo'ealarm.

6hich of the following is trueE

A 4obalt -&2 is used as a radioactivesource.

* The device wor's based on the penetratingpower of the radioactive radiation

+ 6hen a fire brea's out, the particles ofsmo'e will absorbs the alpha particles

, The particles of smo'e increase theionisation of the air and the alarm will beactivated

4 The diagram shows a graph of activity of Iodin-"" present in the thyroid against time of threepatients /, G and R when the Iodin-"" arein$ected into the body of the patients.

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6ho is has a normal thyroid glandE

A /atient /* /atient G+ /atient R

15 6hat is the radioisotope that can be used todetermine the age of a fossilE

A 4arbon-"!* Iodine-""+ Radon-,


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1 * container containing a radioactive waste issubmerged in a pool of water to

A cool them* solidify the waste+ stop the rays from escaping

, slow down the decay process

14 The diagram shows a radioactive source and adetector are used to chec' the level of fruit $uicein a carton. 4artons of fruit $uice pass betweenthe detector and the radioactive source. Theradioactive source emits β- particles.

(a) State the name of a suitable detector of theβ- particles.

HHHHHHHHHHHHHHHHHHH(b) 6hat is a β- particleE

HHHHHHHHHHHHHHHHHHH

(c) @+plain why the level of detected radiationfalls when a full carton of $uice goes pastthe detectorE

HHHHHHHHHHHHHHHHHHH(d) @+plain

(i) why a source emitting α - particles isnot used.

HHHHHHHHHHHHHHHH..

HHHHHHHHHHHHHHHH..

HHHHHHHHHHHHHHHH..(i) why a source emitting γ - rays is not

used.

HHHHHHHHHHHHHHHH..

HHHHHHHHHHHHHHHH..

25 The diagram shows the process of controllingthe thic'ness of metal plates.

The reading obtained are shown in the tablebelow?

/osition ofmetal plate

* C 4 = @ >

Reading ofcounter

count perminute

22 #2 "2 2 "%8 2"

(a) ame the detector /.

.................................................................(b) 6hy the gamma source is usedE

.................................................................

..................................................................(c) 6hy the gamma source is placed in a

plumbum bo+E

................................................................

..................................................................(d) (i) *t what position of the metal is very

thin E

..........................................................(ii) 0ive one reason for your answer in

d(ii).

HHHHHHHHHHHHHHHH.

HHHHHHHHHHHHHHHH.(e) @+plain why the thic'ness of the metal

plate at position *,=,@ and > are same butgive the different readingsE

..................................................................

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(f) 6hat happen to reading of the counter if apart of the metal plate attached withmagnetE

....................................................................(g) (i) If the gamma source is removed,

what happen to the reading of thecounterE

............................................................(ii) 0ive the reason for your answer in

g(i).

............................................................

............................................................

21 * smo'e detector fitted inside a house contains

a radioactive source americium !".(a) 4omplete the following table of information

for an atom of americium !".

umber of neutrons "!&

umber of protons %#

umber of electrons

(b) The diagram shows that the radiation givenout by americium !" does not go throughpaper.

6hich type of radiation, alpha (α) ,beta (β) or gamma (γ) is given out byamericium !"E

HHHHHHHHHHHHHHH....(c) @+plain why the radiation given out by

the americium !" is unli'ely to doany harm to people living in thehouse.

(d) 4omplete the sentence by choosingan answer from the bo+.

*fter many years the radiationemitted by americium !" will be

JJJJJJJJJJJJJJJJJJ the smo'edetector was new.

22 (a) =iagram(a) shows a bo+ containing adangerous material.

=iagram (a)

(i) 6hat is material is 'ept in the bo+E

HHHHHHHHHHHHHHH..(ii) State one negative effect of the

material to the peopleE

HHHHHHHHHHHHHHHH.(iii) 0ive t6o safety precautions which

should be ta'en when handling thematerialE

HHHHHHHHHHHHHHHH.

HHHHHHHHHHHHHHHH.

(b) * doctor uses radioactive rays to detect theflow of blood in a patient. The device isshown in =iagram (b) and its resultsrecorded are shown in =iagram(c).

=iagram(a)

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less than more than the same as


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=iagram (b)

(i) ame a radioisotope is used.

HHHHHHHHHHHHHH

(ii) State the type of radioactive rayemitted.

HHHHHHHHHHHHHH.

(iii) The radioisotope used has a shorthalf-life. @+plain whyE

HHHHHHHHHHHHHHHH

HHHHHHHHHHHHHHHH(iv) 6hy is there a pea' in the graphE

HHHHHHHHHHHHHHHH.

HHHHHHHHHHHHHHHH.

HHHHHHHHHHHHHHHH.(c) * detector shows the activity of a

radioisotope decreases from "&2 countsper second to 2 counts per second in "#minutes. 4alculate the half-life of theradioisotope.

23 *s a researcher , you are assigned toinvestigate the characteristics of a certainradioactive isotope that could be used to detectthe thic'ness of paper in a paper factory.(a) 6hat does the term isotope meanE

(b) The table below shows the characteristicsof five isotopes.

Isotope 4haracteristics of isotope

State ofmatter

@mittedradiation

3alf-life

/enetratingpower

Strontium-%2

Solid Ceta years

1edium

4obalt-&2 Solid 0amma #years

3igh

enon-" 0as Ceta #days

3igh

6atercontaining3-

:i5uid Ceta "years

1edium

/olonium-"2

Solid *lpha "!2days

:ow

Cased on the table aboveA

(i) @+plain the suitable characteristics ofthe isotopes so that it can be used tomeasure the thic'ness of paper in apaper industry.

(ii) Select the most suitable isotope to beused in detecting the thic'ness ofpaper in the factory and give yourreason.

(c) Suggest briefly the arrangement of thepaper thic'ness detector apparatus and

state how radioactivity is used to detect thethic'ness of the paper.

(d) S'etch a graph activity against time toillustrate how radioactive materials decay.


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(ii) @+plain why the rays follow the pathshown in =iagram (b).

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