RadioactivityCopy
1. Which instrument is commonly used to detect alpha radiation?
A. Thermometer
B. Spark counter
C. Barometer
D. Altimeter
2. Which device is used to detect beta and gamma radiation?
A. Mercury thermometer
B. Spark plug
C. Geiger-Müller tube
D. Ammeter
3. What unit is used to measure radiation count rate?
A. Bq
B. V/m
C. counts/s or counts/min
D. Hz
4. Background radiation is:
A. Radiation from nuclear plants only
B. The radiation produced in a laboratory
C. Radiation that is always present in the environment
D. Non-ionising radiation
5. Which of the following contributes significantly to background radiation?
A. Moonlight
B. Wind
C. Cosmic rays
D. UV light
6. Which gas contributes to background radiation from the air?
A. Oxygen
B. Nitrogen
C. Radon
D. Argon
7. How is corrected count rate calculated?
A. Measured count rate – background count rate
B. Background count rate ÷ time
C. Count rate × background radiation
D. Add background to the reading
8. Which of the following statements is true about radioactive decay?
A. It is controlled by temperature
B. It can be predicted accurately
C. It occurs randomly and spontaneously
D. It only occurs under lab conditions
9. Alpha particles consist of:
A. Two protons
B. One electron
C. Two protons and two neutrons
D. One proton and one neutron
10. Beta particles are:
A. Fast-moving protons
B. Neutrons
C. High-speed electrons
D. Positrons
Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Physics Full Scale Course
11. Gamma radiation is best described as:
A. A stream of protons
B. A fast-moving neutron
C. A high-frequency electromagnetic wave
D. A positive charge
12. Which radiation has the strongest ionising power?
A. Gamma
B. Beta
C. Alpha
D. Neutron
13. Which radiation can be stopped by paper?
A. Gamma
B. Beta
C. Alpha
D. Neutron
14. Which radiation can penetrate several centimetres of lead?
A. Alpha
B. Beta
C. Gamma
D. Neutron
15. Which type of radiation is deflected most in electric fields?
A. Alpha
B. Beta
C. Gamma
D. None
16. Which radiation is not deflected in magnetic or electric fields?
A. Alpha
B. Beta
C. Gamma
D. All of them
17. In a nuclear reaction, which particle causes uranium-235 to undergo fission?
A. Proton
B. Neutron
C. Alpha particle
D. Electron
18. What is produced in a nuclear fission reaction of U-235?
A. Two smaller nuclei and one neutron
B. Two daughter nuclei and energy
C. Hydrogen atoms
D. Only energy
19. Which of the following is necessary for a fusion reaction?
A. Low temperature and high pressure
B. High temperature and high pressure
C. Room temperature
D. Chain reaction
20. Where does fusion naturally occur?
A. Inside Earth
B. In stars
C. In nuclear power plants
D. In the atmosphere
Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Physics Full Scale Course
21. What is a chain reaction?
A. A single step process
B. One decay causes another, repeatedly
C. Two decays cancel each other
D. A reaction that breaks bonds in chains
22. Which component in a nuclear reactor slows down fast neutrons?
A. Control rods
B. Shielding
C. Moderator
D. Coolant
23. Which part of the reactor absorbs excess neutrons to control the chain reaction?
A. Fuel rod
B. Control rod
C. Moderator
D. Cooling fan
24. What is the function of the coolant in a nuclear reactor?
A. Absorbs neutrons
B. Absorbs heat and transfers it away
C. Slows down the chain reaction
D. Creates electricity directly
25. What is meant by half-life?
A. Time for all atoms to decay
B. Time for a nucleus to decay
C. Time for half the nuclei in a sample to decay
D. Time for radiation to stop completely
26. A radioactive sample has a half-life of 10 days. How much remains after 30 days?
A. 1/3
B. 1/2
C. 1/8
D. 1/4
27. Which isotope is used in carbon dating?
A. C-12
B. C-13
C. C-14
D. C-16
28. Which radiation is used in smoke alarms?
A. Beta
B. Gamma
C. Alpha
D. Neutron
29. Which radiation is used to sterilise surgical equipment?
A. Alpha
B. Gamma
C. Beta
D. Infrared
30. What radiation is used in cancer treatment?
A. Alpha
B. Beta
C. Gamma
D. Neutron
31. What is one effect of ionising radiation on living cells?
A. Cell multiplication
B. Increased growth rate
C. Mutation or cell death
D. Increased strength
32. Which of the following reduces radiation exposure?
A. Using water
B. Increasing contact time
C. Increasing distance and using shielding
D. Storing in glass jars
Answer key and explanations
1. Correct Answer: B
Explanation: Spark counters and cloud chambers are used to detect alpha radiation.
2. Correct Answer: C
Explanation: Geiger-Müller (GM) tubes are commonly used to detect both beta and gamma radiation.
3. Correct Answer: C
Explanation: Count rate is measured in counts per second (counts/s) or counts per minute (counts/min).
4. Correct Answer: C
Explanation: Background radiation is the natural radiation present in the environment at all times.
5. Correct Answer: C
Explanation: Cosmic rays are high-energy particles from outer space contributing to background radiation.
6. Correct Answer: C
Explanation: Radon gas is a natural radioactive gas found in air that contributes to background radiation.
7. Correct Answer: A
Explanation: Corrected count rate = Measured count rate – Background radiation.
8. Correct Answer: C
Explanation: Radioactive decay is spontaneous and cannot be predicted for individual atoms.
9. Correct Answer: C
Explanation: Alpha particles are helium nuclei: 2 protons + 2 neutrons.
10. Correct Answer: C
Explanation: Beta particles are high-speed electrons ejected from the nucleus.
11. Correct Answer: C
Explanation: Gamma rays are high-energy electromagnetic radiation with no mass or charge.
12. Correct Answer: C
Explanation: Alpha particles are the most ionising due to their mass and charge.
13. Correct Answer: C
Explanation: Alpha radiation is easily stopped by a sheet of paper.
14. Correct Answer: C
Explanation: Gamma rays are very penetrating and can go through thick lead.
15. Correct Answer: B
Explanation: Beta particles are lighter and more easily deflected by electric fields.
16. Correct Answer: C
Explanation: Gamma rays have no charge, so are not deflected by electric or magnetic fields.
17. Correct Answer: B
Explanation: Neutrons initiate the fission of uranium-235.
18. Correct Answer: B
Explanation: Fission of U-235 produces daughter nuclei, 2 or 3 neutrons, and energy.
19. Correct Answer: B
Explanation: Nuclear fusion requires very high temperatures and pressures to overcome repulsion.
20. Correct Answer: B
Explanation: Stars generate energy through nuclear fusion.
21. Correct Answer: B
Explanation: In a chain reaction, the neutrons from one fission event cause more fissions.
22. Correct Answer: C
Explanation: Moderators slow down neutrons to increase the chance of further fission.
23. Correct Answer: B
Explanation: Control rods absorb neutrons and control the chain reaction rate.
24. Correct Answer: B
Explanation: Coolant removes heat from the reactor core and transfers it to turbines.
25. Correct Answer: C
Explanation: Half-life = time taken for half of the radioactive nuclei in a sample to decay.
26. Correct Answer: C
Explanation: After 3 half-lives (30 days), 1/8 of the original sample remains (½ × ½ × ½).
27. Correct Answer: C
Explanation: Carbon-14 is used in radiocarbon dating to estimate the age of organic materials.
28. Correct Answer: C
Explanation: Alpha particles (typically from Americium-241) are used in smoke detectors.
29. Correct Answer: B
Explanation: Gamma rays are used to sterilise medical equipment because they can kill bacteria.
30. Correct Answer: C
Explanation: Gamma radiation is used to kill cancer cells in radiotherapy.
31. Correct Answer: C
Explanation: Ionising radiation can damage DNA, causing mutations or cell death.
32. Correct Answer: C
Explanation: To reduce radiation exposure: use shielding, limit exposure time, and stay at a distance.