SOAL Radioactivitas

1

The data below shows the amount of radioactivity given off by a radio-isotope as measured by a Geiger-Muller counter over a period of eight hours.

time in hours 0 2 4 6 8
counts per minute (cpm) 500 356 250 178 125

Which of the following is the half-life of the radio-isotope? [rad-59]
 

  a.   4 hours
  b.   250 cpm
  c.   125 cpm
  d.   8 hours

 

2

Which of the following may have increased the level of background radiation? [rad-96]
 
      microwave ovens
      exploring space
      nuclear reactors
      mobile telephones

 

3

The radioactivity due to naturally occuring uranium minerals in rocks contributes to what is known as? [rad-122]
 
      solar radiation
      surrounding radiation
      atmospheric radiation
      background radiation

 

4

Which of the following radiations is measured with a geiger counter? [rad-45]
 
      beta
      microwave
      ultraviolet
      infrared

 

5

  Radioactive tracers can be used to find leaks in pipes underground. The gamma emitter, Iridium-183 (half-life 54 minutes) can be used. Why is iridium-183 a suitable radioactive tracer to use? [rad-77]

 

      an alpha emitter would do long-term harm to the environment
      gamma radiation has no harmful effect on wildlife
      beta radiation could not be detected in the soil with a Geiger counter
      the half-life is quite short

 

6

Which of the following statements CORRECTLY describes radioactivity? [rad-79]
 
      the breakdown of unstable nuclei in atoms
      a very exothermic chemical reaction
      a nuclear change that is started by heating the radioactive material
      a chemical reaction that gives out radio waves

 

7

The emissions from four different radioactive sources where tested to see which materials would absorb and stop the radiation. The amount of radiation passing through was measured with a Geiger Counter in counts/second (c/s). From the data, which source gives out mainly ALPHA radiation? [rad-35]

Radioactive Material NO ABSORBER THICK CARD 5 mm ALUMINIUM 2 cm LEAD
Source Q 25 c/s 25 c/s 24 c/s 6 c/s
Source W 27 c/s 1 c/s 0 c/s 0 c/s
Source Y 26 c/s 12 c/s 1 c/s 0 c/s
Source Z 22 c/s 21 c/s 3 c/s 0 c/s

 

      Source W
      Source Z
      Source Q
      Source Y

 

8

  The radioactive isotope Americium-241 (half-life 453 years) emits alpha radiation and is used in smoke detector alarms. The alpha emitter and detector give a constant signal until the alpha radiation is stopped by smoke particles. If the signal changes the alarm is triggered. Why is it essential the radio-isotope has a long half-life? [rad-76]

 

      so the smoke detector will last for hundreds of years
      so the battery doesn’t run down
      so the signal remains constant for several years
      alpha emitters with a long half-life become more active if the temperature rises

 

9

A series of different barriers was placed between a radioactive source and a Geiger-Muller tube and counter. This was to find out which types of radiation was being emitted by the radioactive substance. The results are shown in the table below. Which type or types of radiation were being emitted? [rad-101]

EXPERIMENT COUNT RATE in counts/minute
Background radiation 30
No absorber 2000
Thin paper absorber 30
4 mm thick sheet of aluminium 30

 

      alpha particles only
      gamma rays only
      alpha particles and beta particles
      beta particles and gamma rays

 

10

Which of the following radioactive sources is the most suitable for monitoring any holes in a fast moving paper production line? [rad-87]
 
      Americium-241, half-life 458 years, emits alpha radiation
      Chlorine-36, half-life 30000 years, emits beta radiation
      Technitium-99, half-life 6 hours, emits gamma radiation
      Iridium-183, half-life 54 minutes, emits gamma radiation

Top of Form

1

One gram of each of the following chemicals was placed at a distance of 2 cm from a Geiger-Muller tube and counter. The results are given below. The background count was found to be 34 counts/minute. Which chemical is the most radioactive? [rad-92]
 
      calcium carbonate, 39 counts/min
      copper sulphate, 52 counts/min
      sodium chloride, 35 counts/min
      potassium chloride, 72 counts/min

 

2

Which of the following may have increased the level of background radiation? [rad-96]
 
      mobile telephones
      microwave ovens
      nuclear reactors
      exploring space

 

3

Radium-227 undergoes radioactive decay. What new isotope is formed? [rad-145]
 
       
       
       
       

 

4

Gamma radiation is used to treat cancer in hospitals. The radiographer performing the treatment is best protected behind a shield of? [50]
 
      brick
      aluminium
      lead
      cardboard

 

5

  The radioactive isotope Americium-241 (half-life 453 years) emits alpha radiation and is used in smoke detector alarms. The alpha emitter and detector give a constant signal until the alpha radiation is stopped by smoke particles. If the signal changes the alarm is triggered. Why is it essential the radio-isotope has a long half-life? [rad-76]

 

      so the battery doesn’t run down
      alpha emitters with a long half-life become more active if the temperature rises
      so the smoke detector will last for hundreds of years
      so the signal remains constant for several years

 

6

The properties of four particles are described below. Which is an electron? [rad-7]
 
      mass = 1/1850, electric charge = -1
      mass = 4, electric charge = +2
      mass = 1, electric charge = +1
      mass = 1, electric charge = 0

 

7

The penetration and absorption properties of different types of radiation are described below. Which of them describes the behaviour of beta radiation? [rad-5]
 
      stopped by 0.1mm of paper
      passes through paper, 4cm of steel or 100cm of lead
      passes through paper or 4cm of steel, but stopped by 100 cm of lead
      passes through 0.1mm of paper, but stopped by 4cm of steel

 

8

The emissions from 4 radioactive sources where tested to see which materials would absorb and stop the radiation. The amount of radiation passing through was measured with a Geiger Counter in counts/second (c/s). From the data, which source gives out mainly BETA and GAMMA radiation? [rad-40]

Radioactive Material NO ABSORBER THICK CARD 5 mm ALUMINIUM 2 cm LEAD
Source Q 25 c/s 25 c/s 24 c/s 6 c/s
Source W 27 c/s 1 c/s 0 c/s 0 c/s
Source Y 26 c/s 12 c/s 1 c/s 0 c/s
Source Z 24 c/s 23 c/s 10 c/s 0 c/s

 

      Source Q
      Source Z
      Source W
      Source Y

 

9

The half-life of radioactive thorium-234 is 24 days. A sample contains 8g of thorium-234. After how many days will it contain only 4g of thorium-24? [rad-103]
 
      72 days
      96 days
      48 days
      24 days

 

10

Which of the following radioactive sources is the most suitable for monitoring the thickness of a fast moving production line of aluminium? [rad-86]
 
      Chlorine-36, half-life 30000 years, emits beta radiation
      Iridium-183, half-life 54 minutes, emits gamma radiation
      Technitium-99, half-life 6 hours, emits gamma radiation
      Americium-241, half-life 458 years, emits alpha radiation

 

Leave a comment

No comments yet.

Comments RSS TrackBack Identifier URI

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s