FIZIKMOZAC 2010 CHAPTER 10: RADIOACTIVIT 1. Question 1: Tre ngg anu A radioactive source emits tw and Q is placed in front of an field and the radioactive path i in Diagram 1. DIAGRAM 1 (a) Name the mat erial of con t ............................................. (b)(i) Compl ete this sentence underli ning one correct the box. Ray P is (ii) Give the reason for yo in (a)(i). ......................................... (c) Why the size of def lection greater than ray Q? ............................................ an alpha partic le a beta parti cle a gamma ray07 rays P lectric s shown iner X. ............. [ 1mark] by phrase in [1mark] r answer................. [1mark] of ray P is ................ [1mark] 2. Ques tion 4: Tre n A Polonium nucleus emit and gamma ray to becom nucleus. (a) Complete the decay e Polonium nucleus by appropriate number in provided. (b) The Polonium nucle front of electric field Diagram 4.1. (i) Draw path of particle and g Diagram 4.1. (ii) Exp lai n why t the path as yo Diagram 4.1 Alpha: ........................... Gamma: ......................... (c) A sample of polo 120 g has a half-l Determine the m that has decayed second. ganu 08 alpha particles a Plumbum uation forriting the the boxes [1 mark] s is placed in as shown in ay for alpha mma ray in [2 marks] e rays follow u drawn in .......................... ......................... [2 marks] nium of mass ife of 45 s. ss of polonium after 180 [2 marks]
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(ii) Which radioactive materiadecay at a faster rate? Exanswer.
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8. Question 6: Kedah 09Diagram 6.1 shows the activitradioactive substance X and aradioactive substance Y beingmeasured by a Geiger-Muller tconnected to a rate meter.
Diagram 6.2 shows the decayobtained for radioactive subst
and radioactive substance Y.
l willlain your
.................
................[2 marks]
of a
ube
curvesance X
(a) What is the mean
……………………
(b) Based on the de
Diagram 6.2,(i) State the half-
radioactive suradioactive su
X: ...................
Y: ...................
(ii) For radioactiv
and radioactiwhat percentadecayed after
X: ...................
Y: ...................
(c) Based on the anand 6(b)(ii), com
rates of radioactiand radioactive sHence state the r between decay r
.............................
.............................
ing of half life?
…………………[1 mark]
ay curves in
life of bstance X andbstance Y.
..........
.......[2 marks]
e substance X
e substance Y,ge remains un10 minutes?
.........................
.........................[2 marks]
wers to 6(b)(i)are the decay
ve substance Xubstance Y.elationshipte and half life.
(iv) Using Table 8, what imaximum distance α-can travel in air?
.......................................
(v) Justify your answer to
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10.Question 2: SBP 08A radioactive source and a deused to check the level of fruicarton. Cartons of fruit juice pbetween the detector and theradioactive source, as shoDiagram 2. The radioactive so
-particles.
(a) What is a -particle?
...........................................
(b) State the suitable detecto
-particles in Diagram 2.
...........................................
(c)(i) What happened to the r the rate-meter when a f of juice goes past the d
.........................................
thearticles
.................[1 m a r k ]
c(iv).
.................
.................[2 m a r k s ]
ector are juice in a
ass
n inrce emits
.................[ 1 m a r k ]r to detect
..................[ 1 m a r k ]ading of ll cartontector.
................[ 1 m a r k ]
(ii)Give the reason f
.............................
(d) Explain why a sou
particles is not suias a radioactive so2.
........................................[ 1 m a r k ]
11.Question 8: TeknDiagram 8.1 shows a racan be used to control
paper as it is manufacttube reading at P, Q anas shown in table 8.2
.............................................................[2 m a r k s ]
(c) Table 8.3 shows the time taken todecay to 12.5 % from the originalvalue of the three isotopes withthe type of radiation given outduring the process.
Radioisotopes
Timetaken
todecay12.5%
Type of radiation
givenout
thorium-231 3
days Beta
Kobalt-60 15.9
years Gamma
Actinium-227 66
years
Beta
TABLE 8.3
Base on Table 8.3,
(i) Write the decay equation of
Radium-226 ( Ra226
88 ) to Radon
( Rn222
86 ).
[2 m a r k s ]
(ii) Determine the half life of eachradioisotopes
[4 m a r k s ](d) Based your answer in (c)(ii) and
Table 8.3, which one of theradioisotope would be the bestchoice as the radioactive source.Give two reason for your answer
.............................................................[3 m a r k s ]
12.Question 8: Trengganu 07Diagram 8.1 shows a method used todetect leakage of pipes laid
underground. A little radioisotopesubstance is dissolved in the water thatflows in the pipes. A Geiger Muller which connected to the ratemeter isthen moved over the pipes accordingto the layout plan of the undergroundpipes.
Table 8.1 shows the readings of theratemeter at the different location.
.............................................................[2 m a r k s ]
(c) Table 8.2 shows the time taken for radioisotope of Sodium-24, Cobalt-60 and Radium-226 to decay to12.5% from initial activity andradioactive emission.
Radioisotope
Timetaken todecay
to12.5%
Radioactiveemission
Sodium -24 45hours
Beta
Cobalt-60 15.9years
Gamma
Radium-226 4860
years
Alpha
Base on Table 8.2,(i) Write the decay equation for
Radium-226 ( 226
88Ra ) if it
decays to Radon ( 222
86 Rn ).
[2 m a r k s ](ii) calculate the half life for every
radioisotope.
[4 m a r k s ](d) Based on your answer in (c) (ii) and
Table 8.2, suggest the suitableradioisotope to detect the leakagesof pipes.
(c) Determine the most suitableradioisotope that can be used todetect the leakage.
…………………………………………[1 mark]
(d) The radioisotope in 8(c) has aninitial count rate of 1600 countsper minute. Calculate the timetaken for the radioisotope in thewater to become 100 count per minute.
[2 marks](e) Cobalt-60 emits gamma ray.
(i) State one property of thegamma ray.
……………………………………….[1 mark]
(ii) Compare the speed of gammaray and speed of light in thevacuum.
.......................................................14.Conceptual: Johor 07
Diagram 10.1 and Diagram 10.2 showthe graph of radioactivity for twodifference sources .
(a) Using Diagram 10.1 andDiagram 10.2, compare timeelapsed, radioactivity decayand initial activity for the twosources.
[3 m a r k s ]
(b) State the relationship betweenthe fraction of radioactivesource that remains and thetime elapsed to deduce arelevant physics concept.
15.Understanding: Johor 07The proton number of uranium (U) is 92.Uranium-236, one of the uranium
radioisotopes, decay to thorium (Th) byemitting an alpha particle.(i) Write the nuclear equation
expressing the alpha decay of U236
92
(ii) Briefly describe the change whichoccurs in the nucleus of uranium-236 during the decay.
[4 m a r k s ]
16.Understanding: Perak 07X, Y and Z are three different radioactivesubstances. It is known that one of them emits only α particles another oneemits only β particles, and the thirdemits only γ particles. You are requiredto carry out investigation to identify thetype of radiation emitted by the threetypes of substances.
(i) Draw a diagram to show howyou carry out theinvestigation.
(ii) Describe the procedures andexplain how you arrived at theconclusion.
[7 marks]
17.Understanding: Kedah 07What is nuclear fission and nuclear fusion? Explain how these two nuclear
reactions are able to release energy?
[4 m a r k s ]
18.Qualitative problems: Kedah 07Diagram 10.3 shows an underground water pipe which has a leak.
(i) Explain how a radioactive substancecan be used to detect the location of the leakage.
[4 m a r k s ]
(ii) Radioactive substances arehazardous and must be used withcare. In using a radioactivesubstance to detect the leakage,
suggest how the substance shouldbe chosen by considering thefollowing aspects:- the half-life of the substance,- the types of radiation emitted by
the substance,- the type of detector to be used.
[6 m a r k s ]
19.Qualitative problems: Johor 07A doctor wants to detect the presence
of blockages in the blood vessels. Byinjecting a suitable radioisotope astracer into the blood stream of thepatient, a doctor should able to identifythe part of body that not receivingenough blood.
Using your knowledge on radioactivityand Diagram 10.3, explain on thefollowing aspect:
(i) what radioactiveand equipment cto monitor the blthe patient.
(ii) how the equipmassembled.
(iii) how the system
20.Making Decision: PerakThe water supply to your scha large storage tank situated ischool compound. There is adrop in the water pressure at tyour school. You suspect thatcould be due to a big leak in t
underground water pipes. Tabgives the list of materials andequipment that could be usedthe leak.
Radioactivesource
Radiationemitted
P α 1
Q β 2
R β 1
S γ 40
Detector
Spark counter Cloud chamber
Geiger-Muller tube
Radiationbadge
(i) What is meant by thlife?
(ii) Explain the suitabiliradioactive source,detector and the cobe used to locate thto detect the radiatiand justify your cho
materialn be usedod flow in
nt is
orks.[10 m a r k s ]
07ol is from
theudden
he taps inthise
le 12
to locate
alf-life
hours
0 days
hours
minutes
Counter
Scaler atemeter
e half-[1 mark]
ty of thethe
nter toe leak and
n emittedice.[10 marks]
21.Section B: MaraAs a researcher, you ar investigate the charactradioactive substanceshal-lives to be used for cancer. Diagram 12.1 s
radioactive rays directecancer cells in a patien
(a) What is meant b
(b) Sketch a graph otime to illustratea radioactive subyour graph to ex
half-life is deter
Table 12.1 shows the pradioactive substancesRadio-activesource
Type of radiation
Half-life
J Beta 1620years
K Gamma 6hour
L Gamma 5.27years
M Beta 15days
(c)(i) Based on Table 12explain the suitab
8e assigned toristics of with differentthe treatment of hows
d towards the’s brain.
half-life?[1 mark]
activity againsthe decay rate of stance. Uselain how the
(ii) Radioactive substanceshazardous and must be ucare. In using a radioactisubstance to study the infertilizer, suggest how thsubstance and the detectbe chosen by considerinfollowing aspects:- The half life of the sub- The type of radiation
the substance- The type of detector t
23.Section C: Kelantan 08Radioactive material has somimportant uses in the field of such as to study the effectivefertilizers and control the poppests.
(a) A researcher conducteinvestigation using posto study the absorptionmovement of fertilizersplant. Diagram 12.1 shoradioisotope posphoruinjected to the stem of tThe half-life of posphor 14 days and emits β-pa
carried
4 marks]
resed withvetake of
or shouldthe
stancemitted by
be used.[6 marks]
gricultureess of lation of
anhorus-32andin the
s how-32 is
he plant.s-32 is
ticles.
Based on the informatiradioactivity and Diagr
(i) What is mean
(ii) What is β-part
(iii) Name the modetector couldetect β-parti
(b) The initial posphis 800 counts per Calculate the timphosphorus-32 adecrease to 50 csecond.
(c) The population ocontrolled usingradioactive sour
You are assignecharacteristics oradioisotopes thsuitable for use ipopulation of peTable 12.2 shows
Explain the suitability of thecharacteristics of the radioisotope to beused in the controlling the population of pests based on the following aspects:- State of matter - Types of ray- Half-lifeDetermine the most suitable
radioisotope to be used and give thereason for your choice.
[8 m a r k s ]
(d) The following equation shows afission reaction of Uranium-235.
(i) What is meant by a nuclear fission?
[1 m a r k ]
(ii) Nuclear fission produces achain reaction. Describe howthe chain reaction occurs in anuclear fission of an atom of Uranium- 235.
[4 marks](iii) The nuclear energy produced
in the fission reaction of uranium-235 is 2.9 x 10-11 J.Calculate the total loss of mass in the reaction.[ c = 3.0 x 108 ms-1]
[2 marks]
24.Section C: Kelantan 09As a researcher, you are assigned toinvestigate the characteristics of acertain radioactive i s o t o p e that could beused to detect the thickness of paper inpaper factory.
(a) What is meant by radioi s o t o p e ?
(b) Table 12 below shows thecharacteristics of fiveradioisotopes.
Radioisotope
Characteristics of IsotopeStateof matter
Emittedradiation
Half-life
Power of penetra-tion
Strontium-90
Solid Beta 28years
medium
Cobalt-60 Solid Gamma 5years
High
Xenon-133 Gas Beta 5days
High
Water H-3 Liquid Beta 12years
Medium
Polonium-210
Solid Alpha 140days
Low
Based on the table above;(i) Explain the suitable characteristics
of the radioisotopes so that it canbe used to detect the thickness of paper in a paper factory.
(ii) Determine the most suitableradioisotope to be used and giveyour reason for your choice.
[10 marks]
(c) Explain the arrangement of thepaper thickness detector apparatusand state how radioactivity is used
to detect the thickness of the paper.[4 marks]
(d) Sketch a graph of activity againsttime to illustrate how radioactivematerials decay. Use your graph toexplain how the half-life isdetermined.
(e) The half-life of cobalt-60 is 5 years.Calculate the time taken for theactivity of this isotope to decay to12.5% of its initial value.
[2 marks]
25.Section C: Melaka 09Diagram 11 shows how a doctor usedradioisotope to detect the blood flow in
patient’s leg. The radioisotope is takeninto the patient’s body before undergothe treatment.
(a) The patient in Diagram 11 isbeing diagnosis with a present of radioactive in his blood stream.Describe how the radioisotopeget into his body and how thedoctor diagnosis his disease byusing this method.
[4 marks]
(b) Table 11.1 shows the characteristicsof five radioisotopes, P, Q, R, S andT.
Radio-Isotope
P Q R S T
Half-life 5 min 8 6 5.27 7
days hours years hour
Ionizingpower
Low High Low Medium High
Penetrationpower
High Low High High Low
Radia
tion ray
gama alfa gama eta alfa
State of matter
iquid Solid iquid Solid liquid
As a medical officer, you are required tochoose the most suitable radioisotopeas a raditherapy treatment for a braintumor. Study the characterictics of allthe five radioisotope based on thefollowing aspects:
- Half-life
- The ionizing power
- The radioactive radiation- The states of matter
Explain the suitablity of the aspects.Justify your choice.
[10 marks]
26.Section C: SBP 09
Diagram 12.1 shows a system used in afactory to ensure the volume of guava
juice in a bottle is uniform.
The radioactive source, radiationdetector and counter are used to detectthe volume of guava juice. The radioactive sourcecontains a radioisotope.
characteristics of fiveradioisotopes P, Q, R, S and T.
As a factory engineer, you are requiredto determine the most suitableradioisotope that can be used by thesystem to ensure the volume of guava
juice is uniform. Study thecharacteristics of all 5 radioisotopesand explain the suitability of theaspects. Determine the most suitableradioisotope and give the reason for your choice.
[10 marks]
(c) Table 12.3 shows the reading of therate meter for 6 bottles throughdetector and radioactive source.
Bottle Rate meter reading /Count per minute
A 464
B 468
C 467
D 462
E 568
F 470
(i) State one detector that is
suitable to be used for thispurpose.
[1 mark](ii) Based on table 12.3, which
bottle shows the least volumeof juice and state the reasonfor your answer.
[3 marks]
(d) In a radioactive decay series,Uranium-238 decays to becomeRadium-226 by emitting alfa andbeta.