Physics · Chemistry

Radioactivity and Nuclear Physics

519 Questions

Radioactivity and nuclear physics encompass the study of radioactive decay processes, neutron to proton ratios, and nuclear medicine. Questions cover various detection mechanisms, including scintillation counters and neutrino telescopes. These concepts are frequently tested in advanced science and civil services examinations.

Radioactive decayNuclear medicineParticle detectionNeutrino telescopesCosmic ray detection

Radioactivity and Nuclear Physics Questions

Multiple choice

Directions: Fill in the numbered blank (iv) with the best option from those given.

Directions: Fill in the numbered blank with the best option from those given.

Radium is a radioactive element. Let us see what “radioactive” _____ (i) ____. Radioactive elements do not change from year to year. But a few of the heaviest atoms break down and change into other kinds. This breakdown or ____ (ii) _____ is called “radio activity”. Each radioactive element _____ (iii) ____ by giving off rays at a certain rate. This rate cannot be _____ (iv) ____ or slowed down by any known method. Some changes occur rapidly, others slowly, but in all cases the action cannot be _____ (v) ______ by man.

  1. moved

  2. changed

  3. speeded up

  4. explained
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The text states the rate of radioactive disintegration "cannot be ____ or slowed down by any known method." The answer is "speeded up" - making it faster. "Moved" and "explained" don't fit the context of altering a rate. "Changed" is too vague; the sentence specifically discusses accelerating the rate.

Multiple choice

Directions: Fill in the numbered blank (v) with the best option from those given.

Directions: Fill in the numbered blank with the best option from those given.

Radium is a radioactive element. Let us see what “radioactive” _____ (i) ____. Radioactive elements do not change from year to year. But a few of the heaviest atoms break down and change into other kinds. This breakdown or ____ (ii) _____ is called “radio activity”. Each radioactive element _____ (iii) ____ by giving off rays at a certain rate. This rate cannot be _____ (iv) ____ or slowed down by any known method. Some changes occur rapidly, others slowly, but in all cases the action cannot be _____ (v) ______ by man.

  1. diagnosed

  2. controlled

  3. caused

  4. highlighted
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sentence states radioactive action "cannot be ______ by man." "Controlled" is correct because humans cannot alter, influence, or stop radioactive decay processes. "Diagnosed" refers to identifying conditions, "caused" doesn't fit (humans can cause radiation but not control natural decay), and "highlighted" means emphasized, not controlled.

Multiple choice

Geiger-Muller Counter is used for

  1. Geiger-Muller Counter is used for

  2. Measuring radioactivity

  3. Identifying phytochrome pigments

  4. Measuring the light absorption by chlorophyll
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Geiger-Muller Counter is a radiation detection instrument used for measuring ionizing radiation (radioactivity). Option A duplicates the question text as content. Options C and D refer to botanical techniques unrelated to radiation detection.

Multiple choice

Which of the following is a condition for existence of a radioactive element?

  1. The number of protons and neutrons are nearly equal.

  2. The number of protons exceeds much more than that of the neutrons.

  3. The number of neutrons exceeds much more than that of the protons.

  4. The number of protons exceeds much more than that of the electrons.

  5. The number of electrons exceeds much more than that of the neutrons.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When the number of neutrons exceeds much than that of the protons in a nucleus, it becomes unstable or radioactive.

Multiple choice

Which of the following is a result of an alpha emission from a radioactive element?

  1. The atomic number of the daughter element is increaseed by 2.

  2. The atomic number of the daughter element is decreased by 2.

  3. The mass number of the daughter element is increased by 4.

  4. Atomic number of daughter element is increased by 2, and mass number is increased by 4.

  5. Atomic number of daughter element is decreased by 2, and mass number is decreased by 4.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

When an alpha particle comes out of the nucleus of a radioactive element, the atomic number and the mass number decrease by 2 and 4 respectively.

Multiple choice

Which of the following helps in explaining the phenomenon of radioactivity?

  1. Law of conservation of mass

  2. Law of conservation of charge

  3. Law of conservation of mass and charge

  4. Law of constant and multiple proportion

  5. Law of conservation of charge and constant proportion
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Both the mass and charge remain conserved during disintegration of a radioactive element.

Multiple choice

What of the following is not correct about background radiation?

  1. They are radiations to which we all are exposed even in the absence of visible radioactive sources.

  2. Radium, K-40 and C-14 are some of the sources of these radiations.

  3. They cause serious biological damage to us.

  4. Gamma radiations come from the radioactive rocks in the earth's crust.

  5. They do not exceed the maximum permissible level for human safety.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The background radiations do not cause serious biological damage to us because they do not exceed the maximum permissible level for human safety.

Multiple choice

Which of the following is not correct for gamma radiations? (a) Gamma radiations occur when the parent nucleus is in a state of excitation. (b) They are the electromagnetic waves. (c) Their ionising power is very high. (d) They affect a photographic plate. (e) They do not cause fluorescence.

  1. Only (a)

  2. Only (b)

  3. Both (a) and (c)

  4. Both (b) and (d)

  5. Both (c) and (e)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The ionising power of gamma radiations is very low as they are not composed of charged particles like alpha and beta particles. They cause fluorescence when they are incident on a fluorescent material.

Multiple choice

D.D.T. is an example of

  1. radioactive substance

  2. biodegradable substance

  3. non-biodegradable substance

  4. None of these

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

D.D.T. is an example of non-biodegradable substance. It is a colourless contact insecticide, C14H9Cl5, toxic to humans and animals when swallowed or absorbed through the skin. It contains pesticides. Substances that are not broken down by biological processes are called non-biodegradable substances. 

Multiple choice

Beta-voltaics are generators of electrical current, which use energy from a radioactive source emitting beta particles (electrons). Which of the following is the most commonly used source?

  1. Americium

  2. Uranium

  3. Tritium

  4. Plutonium
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Beta voltaics are generators of electrical current, in effect a form of battery, which use energy from a radioactive source emitting beta particles (electrons). A common source used is the hydrogen isotope, tritium. Unlike most nuclear power sources, which use nuclear radiation to generate heat, which then is used to generate electricity (thermoelectric and thermionic sources), beta voltaics use a non-thermal conversion process; converting the electron-hole pairs produced by the ionization trail of beta particles traversing a semiconductor.