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

Which of the following isotopes of plutonium is one of the three primary fissile isotopes, the other two being uranium-233 and uranium-235?

  1. Plutonium-239

  2. Plutonium-240

  3. Plutonium-238

  4. Plutonium-244
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plutonium is a radioactive actinide metal whose isotope, plutonium-239, is one of the three primary fissile isotopes. To be considered fissile, an isotope's atomic nucleus must be able to break apart or fission when struck by a slow moving neutron and to release enough additional neutrons to sustain the nuclear chain reaction by splitting further nuclei. Fission of a kilogram of plutonium-239 can produce an explosion equivalent to 21,000 tons of TNT. It is this energy that makes plutonium-239 useful in nuclear weapons and reactors.

Multiple choice

Which of the following is the most commonly used medical radioisotope?

  1. Uranium-238

  2. Molybdenom-99

  3. Krypton-81

  4. Technetium-99
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Technetium-99m is a meta-stable nuclear isomer of technetium-99, symbolised as 99mTc, and is used in tens of millions of medical diagnostic procedures annually, making it the most commonly used medical radioisotope.

Multiple choice

Which phenomenon was Henri Becquerel originally investigating in uranium when he discovered the new phenomenon of radioactivity?

  1. Electronegativity

  2. Phosphorescence

  3. Catenation

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

In 1896, Henri Becquerel was investigating phosphorescence in uranium salts when he discovered a new phenomenon which came to be called radioactivity. He, Pierre Curie and Marie Curie began investigating the phenomenon. In the process, they isolated the element radium, which is highly radioactive.

Multiple choice

Which of the following statements is/are true?

  1. Enriched uranium is a type of uranium in which the percent composition of uranium-238 has been increased through the process of isotope separation. 2. 235U is the only nuclide existing in nature (in any appreciable amount) that is fissile with thermal neutrons.

  1. Only 1

  2. Only 2

  3. Both of these

  4. Neither of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement 1 is wrong: Enriched uranium is a type of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Statement 2 is correct: 235U is the only nuclide existing in nature (in any appreciable amount) that is fissile with thermal neutrons. To make any other isotope radioactive, we need to perform either fission or fusion (that means other isotopes aren't naturally available). Enriched uranium is a critical component for both civil nuclear power generation and military nuclear weapons.

Multiple choice

Which of the following isotopes is/are paired incorrectly with its/their application?

a. Uranium - fuel in nuclear reactors b. Cobalt - treatment of cancer c. Iodine - determining age of old wooden objects

  1. a only

  2. b only

  3. c only

  4. a and b

  5. b and c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct option as an isotope of iodine is used in the treatment of goitre. An isotope of carbon, carbon-14 is used in determining the age of old wooden objects.

Multiple choice

Consider the following statements:

  1. Old written material, which cannot be read easily, can be read by ultra violet rays.
  2. Gamma rays carry the maximum energy and used in the treatment of cancer.

Which of the given statements is/are correct?

  1. Only (1)

  2. Only (2)

  3. Both (i) & (2)

  4. Neither of them
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement (1) is wrong. Old written material, which cannot be read easily, can be read by infra red radiations. Statement (2) is correct. Yes, Gamma rays carry the maximum amount of energy, which are used in the treatment of cancer.

Multiple choice

Which of the following statements is true?

  1. The radiant energy of Sun is due to nuclear fission.

  2. Loss of α-particle is equivalent to loss of two protons.

  3. Gamma rays are high energy electrons.

  4. Artificial radioactivity was first discovered by H. Becquerel.

  5. Fission of 1 mole of U-235 release 20.41 x 109 KJ energy.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Fission of an atom of U-235 releases 211.5 MeV energy. Fission of 1 mole of U-235 releases 20.41 x 109 KJ energy. Fission of 1 g of U-235 releases 8.68 x 107 KJ energy.

Multiple choice

Which of the following statements regarding radioactive disintegration series is false?

  1. Starting element of 4n disintegration series is Th-232.

  2. Neptunium series is artificial radioactive disintegration series.

  3. The end product of 4n+2 disintegration series is Pb-206.

  4. The actinium series emits 6α and 4β particles.

  5. The end product of 4n+3 series is Pb-207.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

4n+3 disintegration series (Actinium series) Starting element - U-235 End product -  Pb-207 Emits 7α and 4β particles. Natural radioactive disintegration series

Multiple choice

Which of the following statements is/are not correct?

P. Manganese metal is used as scavenger in making steel. Q. All known isotopes of technetium are radioactive, except 98Tc. R. Rhenium is used in the making of electric furnace windings and spectrophotometer filaments.

  1. Only P

  2. Only Q

  3. Only R

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because technetium (99Tc) was the first man-made element with radioactive properties. All known isotopes of technetium (includes 97Tc, 98Tc) have radioactive properties. It is one of the fission products of uranium. It is obtained by spent fuel rods in nuclear reactors.

Multiple choice

Nuclear technology finds its application in many devices including the smoke detector. Which of the following radioisotopes is the most commonly used in smoke detectors?

  1. Americium – 241

  2. Bohrium – 262

  3. Flerovium – 289

  4. Nobelium – 259
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Most of the smoke detectors work either by optical detection (photoelectric) or by physical process (ionisation), while others use both detection methods to increase the sensitivity to smoke. An ionisation smoke detector uses a radioisotope such as Americium-241 to produce ionisation in air. When a difference due to smoke is detected, an alarm is generated.

Multiple choice

Consider the following facts:

  1. Radioactivity was discovered by Marie Curie.
  2. Radioactive materials produce penetrative rays which have been termed alpha, beta and gamma.
  3. While alpha and beta rays are harmful in large amounts, gamma rays pose no danger to human, plant or animal health.

Which of the above is/are true?

  1. 1 and 2

  2. 2 only

  3. 1 and 3

  4. 1 only
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In 1896, Henri Becquerel was investigating phosphorescence in uranium salts when he discovered a new phenomenon which came to be called radioactivity. He, Pierre Curie and Marie Curie began investigating the phenomenon. In the process, they isolated the element radium, which is highly radioactive. They discovered that radioactive materials produce intense, penetrating rays of three distinct sorts, which they labeled alpha, beta and gamma after the Greek letters. Some of these kinds of radiations could pass through ordinary matter, and all of them could be harmful in large amounts.

Multiple choice

Which of the following are the correct definitions?

  1. Alpha decay – when nucleus emits a particle similar in composition to a Helium nucleus
  2. Beta decay – when nucleus emits a high energy positron
  3. Gamma decay – when nucleus emits very high frequency electromagnetic radiation

  1. 1 and 2

  2. 2 and 3

  3. 1 and 3

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

The three forms of radiation that Becquerel and the Curies discovered are also more fully understood. Alpha decay is when a nucleus releases an alpha particle, which is two protons and two neutrons, equivalent to a helium nucleus. Beta decay is the release of a beta particle, a high energy electron. Gamma decay releases gamma rays, which unlike alpha and beta radiation are not matter but electromagnetic radiations of very high frequency, and therefore energy.

Multiple choice

A radionuclide is

  1. an atom with high energy
  2. an atom with low energy
  3. an atom with an unstable nucleus
  4. also called radioisotope

  1. 1, 2 and 3

  2. 2, 3 and 4

  3. 1, 3 and 4

  4. 1, 2, 3 and 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A radionuclide or a radioactive nuclide is an atom with an unstable nucleus characterised by excess energy available to be imparted either to a newly created radiation particle within the nucleus or via internal conversion. Radionuclides are often referred to by chemists and physicists as radioactive isotopes or radioisotopes.