intro
MCQs 1:
What will be the remaining mass of a certain radioactive substance after two days, given that it has a half-life of 12 hours and starts at 1.00g?
Topic: Radioactive Decay and Half-Life
Correct Answer: D) 0.062g
- The concept in question revolves around the theory of radioactive decay and the idea of half-life, which in this case is 12 hours.
- The half-life represents the time it takes for half of the radioactive substance to decay.
- Therefore, in a 24-hour day, there will be two half-life cycles. Given that the scenario spans two days, this results in a total of four half-life cycles.
- Starting from 1.00g, after the first half-life (12 hours), the mass will be reduced to 0.50g. After the second half-life, it'll become 0.25g, then 0.125g after the third, and finally 0.062g after the fourth half-life.
- Thus, the correct answer is D, "0.062g".
MCQs 2:
The treatment for a cancerous thyroid typically involves the use of which substance?
Topic: Radioactive Isotopes in Medical Treatment
Correct Answer: B) I131
- The question pertains to the use of radioactive isotopes, specifically I131, in the treatment of cancerous thyroid conditions.
- Among the given options, I131 is a radioactive isotope that is widely used in the medical field, particularly for treating thyroid cancer.
- This isotope is administrated orally and then absorbed by the thyroid gland, where it destroys cancer cells.
- Therefore, the correct answer is B, "I131".
MCQs 3:
How does the rate of disintegration of a radioactive element change over time?
Topic: Radioactive Decay Rate
Correct Answer: A) Decreases exponentially with time
- The principle highlighted in this question is the nature of radioactive decay, specifically its rate of disintegration over time.
- The rate of radioactive decay, or disintegration, is a measure of how quickly the atoms within a sample are decaying.
- According to the theory of radioactive decay, the rate of disintegration decreases exponentially with time, not linearly or inversely, and it does not remain constant.
- Consequently, the correct answer is A, "Decreases exponentially with time".
MCQs 4:
What is the half-life of Uranium-238?
Topic: Radioactive Half-Life
Correct Answer: D) 4.5 × 10⁹ years
- This question deals with the concept of half-life, which is a term used in nuclear physics to describe the time it takes for half of a sample of radioactive material to decay.
- In the case of Uranium-238, one of the isotopes of uranium, its half-life is significantly longer than that of Uranium-239.
- The half-life of Uranium-238 is about 4.5 × 10⁹ years, which is much longer than options A, B, and C.
- Thus, the correct answer is D, "4.5 × 10⁹ years".
MCQs 5:
For a radioactive substance with a half-life period of 0.693 years, what would its decay constant be?
Topic: Decay Constants in Radioactive Decay
Correct Answer: D) 1 year-1
- The question refers to the concept of decay constants in the context of radioactive decay. The decay constant is a measure of the rate at which a radioactive substance decays.
- The decay constant, often represented by λ, is calculated as λ = 0.693/t1/2, where t1/2 is the half-life of the radioactive substance.
- Given a half-life of 0.693 years, the decay constant becomes λ = 0.693/0.693, which simplifies to λ = 1 year-1.
- Therefore, the correct answer is D, "1 year-1".
MCQs 6:
Given that the half-life of radium is 1600 years, in what time frame would the Earth lose all its radium due to radioactive decay?
Topic: Radioactive Decay Period
Correct Answer: D) Never
- This question is centered on the concept of radioactive half-life and full decay period.
- Radioactive decay is a process that occurs over an extensive period of time. Despite a specific half-life, a radioactive element never completely decays to zero due to its exponential decay nature.
- Thus, theoretically, the Earth will never lose all its radium due to radioactive decay.
- Therefore, the correct answer is D, "Never".
MCQs 7:
What is the required condition for nuclear fusion to occur?
Topic: Conditions for Nuclear Fusion
Correct Answer: A) High temperature and high pressure
- This question is based on the conditions necessary for nuclear fusion to occur.
- Nuclear fusion is a process where two or more atomic nuclei come together to form a larger nucleus. It requires a high temperature to provide the hydrogen atoms with sufficient energy to overcome the electrical repulsion between protons.
- Additionally, high pressure is needed to bring the hydrogen atoms close enough together to fuse.
- Therefore, the correct answer is A, "High temperature and high pressure".
Question 8:
If only one-eighth of the original mass of a specific radioactive isotope remains undecayed after an hour, what is the half-life of the isotope in minutes?
Topic: Half-life of Radioactive Isotopes
Correct Answer: B) 20 min
- The problem involves the principle of half-life in radioactive decay, where the half-life is the time required for half of a quantity of radioactive isotope to decay.
- When only one-eighth of the original mass remains undecayed, it indicates that three half-lives have passed (since 1/8 is equivalent to (1/2)³).
- Thus, the half-life can be calculated by dividing the total time by the number of half-lives. In this case, the half-life is 60 minutes / 3, which equals 20 minutes.
- Therefore, the correct answer is B, "20 minutes".
Question 9:
Where can electrons be found?
Topic: Electron Location in Atoms
Correct Answer: B) They cannot be found inside the nucleus
- The question pertains to the structure of an atom, particularly the location of electrons.
- Electrons are a fundamental component of atoms and are found in specific regions called electron shells, which surround the nucleus.
- Therefore, electrons only exist outside the nucleus, making option B the correct answer.
Question 10:
What is the approximate percentage of the original quantity of a radioactive material that remains after five half-lives?
Topic: Remaining Quantity after Radioactive Decay
Correct Answer: A) 3%
- The question explores the concept of half-life and how much of a radioactive material remains after a certain number of half-lives.
- After each half-life, the original quantity of the radioactive material is reduced by half. Therefore, after five half-lives, the remaining quantity is (1/2)⁵, which equals 1/32.
- To convert this fraction to a percentage, multiply by 100, leading to approximately 3%.
- Thus, the correct answer is A, "3%".
Question 11:
What is the appropriate measurement unit for the decay constant?
Topic: Measurement Unit for Decay Constant
Correct Answer: B) s^-1
- This question deals with understanding the correct unit for measuring the decay constant in radioactive decay processes.
- The decay constant is represented by λ and is calculated using the formula λ = (ΔN/N)/Δt.
- The unit of the decay constant is inverse seconds (s^-1) since it involves the division of particle count by time.
- Therefore, option B, "s^-1," is the correct answer.
Question 12:
Assuming an element has a half-life of 7 days at standard temperature and pressure (STP), if the temperature is doubled and pressure is halved, what will be the half-life of the element?
Topic: Effects of Temperature and Pressure on Half-Life
Correct Answer: B) 7 days
- This question is designed to test your understanding of the impact of environmental conditions, such as temperature and pressure, on the half-life of a radioactive element.
- The half-life of a radioactive element is independent of external conditions and depends only on the inherent properties of the element.
- Therefore, regardless of the changes in temperature and pressure, the half-life remains the same, i.e., seven days.
- Hence, option B is the correct answer.
Question 13:
If the half-life of substance X is 100μs, how long will it take for the radioactivity of a sample of X to decay to 1/16th of its initial value?
Topic: Time Required for Radioactive Decay
Correct Answer: D) 400 μs
- This question requires an understanding of the concept of half-life and its application in determining the time taken for a sample to decay to a specific fraction of its initial value.
- Given that the half-life of the sample is 100μs, and to decay to 1/16th of its initial value, four half-lives are required (since (1/2)⁴ equals 1/16).
- Therefore, the total time needed will be the half-life of the sample multiplied by four, which results in 400μs, making option D the correct answer.
Question 14:
What is the fundamental principle behind the workings of a Hydrogen bomb?
Topic: Principle of Hydrogen Bomb
Correct Answer: A) Uncontrolled Fusion
- The question aims to ascertain your knowledge about the core principle that drives the functioning of a Hydrogen bomb.
- A hydrogen bomb operates on the concept of uncontrolled nuclear fusion. In this process, the nuclei of two light atoms combine to create a new nucleus.
- Thus, the correct answer is A, "Uncontrolled Fusion".
Question 15:
What is the remaining active quantity of a radioactive substance after one hour, given that its half-life is 20 minutes?
Topic: Remaining Active Quantity of Radioactive Substance
Correct Answer: A) 1/8
- This question requires an understanding of the concept of half-life and how it's used to determine the remaining quantity of a radioactive substance after a certain period.
- Given the half-life of the substance is 20 minutes, three half-lives will have passed in one hour (60 minutes).
- Therefore, the remaining quantity will be (1/2)³, which equals 1/8. So, the correct answer is A, "1/8".
Question 16:
Which element holds the title of being the lightest in the universe?
Topic: Lightest Element in the Universe
Correct Answer: B) Hydrogen
- The question seeks to test your knowledge about the fundamental elements in the universe, specifically the lightest one.
- Hydrogen, with an atomic number of 1, has the simplest atomic structure, making it the lightest element in the universe.
- Therefore, the correct answer is B, "Hydrogen".
Question 17:
What can be said about the decay constant λ of a radioactive sample?
Topic: Radioactive Decay Constant
Correct Answer: C) It remains the same regardless of the atomic age
- The question tests your understanding of the decay constant λ in a radioactive sample.
- The decay constant is a characteristic of the radioactive sample and does not change with the age of the atoms.
- Hence, the correct choice is C, indicating that the decay constant λ is independent of the atomic age.
Question 18:
One curie is roughly equivalent to the number of α-particles emitted from how much mass of radium?
Topic: Radioactive Measurement Unit - Curie
Correct Answer: A) 1 gm
- The question gauges your knowledge about Curie, a unit used in the measurement of radioactivity.
- Originally, one Curie was defined in relation to the α-particles emitted by one gram of radium.
- Thus, option A, "1 gm", is the correct answer.
Question 19:
The disintegration process of a radioactive element can be classified as?
Topic: Radioactive Disintegration
Correct Answer: B) Sporadic
- This question aims to evaluate your understanding of the nature of radioactive decay.
- It is important to note that radioactive decay is a random process, unaffected by physical or chemical changes.
- Therefore, option B, "Sporadic", best describes the disintegration of a radioactive element.
Question 20:
In the human body, where does Cobalt predominantly get absorbed?
Topic: Absorption of Cobalt in the Human Body
Correct Answer: B) Liver
- This question assesses your knowledge about the absorption of specific elements like Cobalt in the human body.
- It is widely recognized that the liver can naturally absorb Cobalt, used as a source of Gamma-ray.
- Consequently, the correct answer is B, "Liver".
Question 21:
Consider a uranium mass of 400g. After passing through 3 half-lives, what amount of uranium will remain?
Topic: Half-life Calculation of Uranium
Correct Answer: A) 50g
- This question checks your comprehension of half-life calculations for radioactive substances, in this case, uranium.
- After three half-lives, the un-decayed uranium mass would be (1/2)³ * initial mass, or 1/8 * 400g, which equals 50g.
- Thus, option A, "50g", is the correct answer.
Question 22:
Radioactivity is primarily linked with which of the following phenomena?
Topic: Phenomenon Associated with Radioactivity
Correct Answer: A) Nuclear decay
- This question seeks to evaluate your understanding of the core phenomenon linked with radioactivity.
- Radioactivity is essentially a nuclear process, closely associated with nuclear decay.
- As a result, the correct answer is A, "Nuclear decay".
Question 23:
A radioactive nuclide initially holds N0 nuclei within a source. After three half-lives have passed, how many of these nuclei have undergone decay?
Topic: Nuclide Decay after Three Half-Lives
Correct Answer: C) 7/8 of N0
- This question assesses your comprehension of the behavior of radioactive nuclides over multiple half-lives.
- After three half-lives, the remaining undecayed nuclei would be (1/2)³ * N0, or 1/8 * N0.
- Consequently, the decayed nuclei can be calculated as the initial amount N0 minus the remaining undecayed nuclei, giving 7/8 * N0.
Question 24:
If an element possesses a half-life of 10 seconds, what would be its mean life?
Topic: Mean Life Calculation
Correct Answer: A) 14.4 seconds
- This question aims to test your understanding of the relationship between half-life and mean life of a radioactive element.
- The mean life (Tmean) is calculated as 1.44 times the half-life (T1/2). Here, Tmean = 1.44 * 10 seconds = 14.4 seconds.
- Hence, the correct answer is A, "14.4 seconds".
Question 25:
What substance is primarily produced as a result of nuclear fusion?
Topic: Product of Nuclear Fusion
Correct Answer: C) Helium
- This question examines your knowledge of the main product of nuclear fusion, a process that primarily occurs in the sun's core.
- In the fusion process, two hydrogen nuclei combine to form a helium nucleus: 1H2 + 1H2 ⟶ 2H4.
- Therefore, the correct answer is C, "Helium".
Question 26:
Radium has a half-life of 1600 years. After 6400 years have elapsed, what fraction of a radium sample would still remain undecayed?
Topic: Half-life Calculation of Radium
Correct Answer: D) 1/16
- This question probes your understanding of how radioactive substances like radium behave over a particular number of half-lives.
- The total time of 6400 years represents 4 half-lives (6400/1600).
- The remaining un-decayed radium fraction can be calculated as (1/2)⁴, which equals 1/16.
Question 27:
Cobalt 60, used in medical procedures, is known to be a strong source of which type of radiation?
Topic: Type of Radiation Emitted by Cobalt 60
Correct Answer: D) γ-rays
- This question checks your knowledge about the types of radiation emitted by specific elements, such as Cobalt 60.
- Cobalt 60 is utilized in medicine due to its strong emission of γ-radiation.
- Consequently, the correct answer is D, "γ-rays".
Question 28:
A polonium (Po) sample's activity fell to one-eighth of its original value after 420 days. What is polonium's half-life?
Topic: Half-Life Determination of Polonium
Correct Answer: A) 140 days
- This question aims to evaluate your understanding of how to calculate half-lives from decay data.
- The activity reduction to one-eighth signifies that three half-lives have passed, as (1/2)³ equals 1/8.
- Therefore, a single half-life is 420 days divided by 3, which equals 140 days.
Question 29:
Which process results in the formation of a heavier atom through the combination of two lighter atoms?
Topic: Process of Forming Heavier Atoms
Correct Answer: C) Nuclear Fusion
- This question is gauging your understanding of nuclear reactions and the processes through which heavier atoms are formed.
- Nuclear fusion is the process in which two or more smaller, lighter nuclei combine to form a larger, heavier nucleus, releasing an enormous amount of energy in the process.
- Thus, the correct answer is C, "Nuclear Fusion".
Question 30:
After 4 hours of disintegration, only 1/16th part of a radioactive substance remains undecayed. What is the half-life of this substance?
Topic: Calculation of Half-Life of a Radioactive Substance
Correct Answer: A) 1 hour
- This question is designed to test your ability to calculate the half-life of a radioactive substance based on a given decay rate.
- The given condition, N=(1/2)ⁿ*N₀, implies that 4 half-lives have passed since the remaining fraction is 1/16 (as (1/2)⁴ equals 1/16).
- Therefore, each half-life is 1 hour (4 hours/4 half-lives).
- Consequently, the correct answer is A, "1 hour".