10 minutes maximum! Can you do it in 5?

Q1+2. When a nucleus emits an α or β particle, it changes to a new element.

1. In this ß decay equation, what are the missing numbers x and y?

 
 
14
 C 14 N
+
y

ß
6
x
-1
  • A. x=5, y=1
  • B. x=5, y=0
  • C. x=7, y=1
  • D. x=7, y=0

2. In the above equation, a particle is missing from the right-hand side of the equation, having no mass or charge.

What is the name of this particle?

  • A. A neutrino.
  • B. An anti-neutrino
  • C. A neutron
  • D. An anti-neutron
3. The half life of an isotope is found to be approximately 1000 years. In a sample, only one eighth (12.5%) of the sample remains, the rest having decayed to a new element.

How old is the sample?

  • A. 125 yrs
  • B. 3000 yrs
  • C. 4000 yrs
  • D. 8000 yrs

4. A weak radioactive source has a measured count rate of 240 counts per minute, and a half life of 3 hrs. However the background count in the lab is 40 counts per minute and needs to be taken into consideration. What will be the expected measured count rate per minute after 6 hours?

  • A. 50
  • B. 60
  • C. 90
  • D. 100

5. An isotope X is shown on the graph below, with A=222 and Z=86. The isotope emits an alpha particle followed by a beta particle. Which letter A to D shows the final position of the isotope?

Nulcear decay - grid view

6. Radioactivity is random and spontaneous. Which of the following best describes these words in this context?

random spontaneous
A
 unpredictable, occurring by chance occurs without outside stimulation
B
 occurs due to forces of nature unpredictable, occurring by chance
C
 occurs without outside stimulation unpredictable, occurring by chance
D
 unpredictable, occurring by chance occurs due to forces of nature

7. A patient in a hospital is injected with a radioactive isotope. Special cameras outside the body can follow the path of the isotope to diagnose medical conditions.

This is known as a medical tracer.

The isotope should give out a specific type of nuclear radiation, and have a suitable half life. Which of the following options is most suitable?

 PET animation
Nuclear Radiation Emitted Half life
A
 β a few hours
B
 γ a few hours
C
 β a few days
D
 γ a few days

8+9. Aluminium foil is made using 2 rollers that squeeze the aluminium into a thin sheet. A radioactive source and a detector are used either side of the sheet to measure how thick the foil is, and make automatic adjustments to the rollers if needed.

  

use of radioactivity in foil mill

8. Which type of radiation should be emitted by the source?

  • A. alpha
  • B. beta
  • C. gamma
  • D. all three would work

9. The half-life of the source needs to be suitable to stop the detector making unnecessary changes to the rollers. How long should the half-life be, and what would happen to the foil thickness if it was the wrong length half-life?

 The half-life should be..... ...otherwise the foil will eventually be made too...
A
 short thick
B
 short thin
C
 long thick
D
 long thin

10. Carbon 14 is used to date radioactive samples. In one sample, only 2 mg of carbon-14 remains, the rest having decayed into 14 mg of stable nitrogen. The half life of carbon 14 is 5700 yrs. How old is the sample?

  • A. 1900 yrs
  • B. 11,400 yrs
  • C. 17,100 yrs
  • D. 45,600 yrs