Welcome to the Unit 18: Atomic and Nuclear Physics! In this comprehensive set of 10th class Physics notes, we delve into the fundamental building blocks of matter and the incredible forces that govern the subatomic realm. From unraveling the mysteries of atomic structure and the periodic table to exploring the awe-inspiring power of nuclear reactions, these notes are designed to equip you with a deep understanding of the intricate interactions that shape our universe. So, fasten your seatbelts and get ready for an enthralling journey through the enigmatic world of atoms and nuclei, where science meets wonder.
10th Physics Unit 18 Long Question Notes
10th Physics Unit 18 Numericals Notes
10th Physics Unit 18 MCQ’s Long Question Notes
- 10th Class Pak Study Textbook
- 9th and 10th Class General Science Textbook
- Chapter No. 9 Notes 10th Chemistry
- Biology 10th Class Past Papers
- English Past Papers of 10th Class
10th Physics Unit 18 Short Question Notes
Who postulated that matter is built from small particles called atoms?
Answer: Greek Philosopher Democritus
What did Rutherford discover about the atom in 1911?
Answer: Rutherford discovered that the atom had a central part called the nucleus.
What are the two types of particles found in the nucleus of an atom?
Answer: Protons and neutrons, collectively called nucleons.
What is the atomic number of an element?
Answer: The atomic number (Z) is equal to the number of protons in the nucleus.
Define isotopes.
Answer: Isotopes are atoms of an element that have the same number of protons but different numbers of neutrons in their nuclei.
What did Becquerel accidentally discover about uranium salt crystals?
Answer: Becquerel accidentally discovered that uranium salt crystals emit invisible radiation that can darken a photographic plate.
Name the three types of radiation emitted by radioactive substances.
Answer: The three types of radiation are alpha (α) particles, beta (β) particles, and gamma (γ) rays.
What are background radiations?
Answer: Radiations present in the atmosphere due to different radioactive substances are called background radiations.
What is cosmic radiation?
Answer: Cosmic radiation is radiation from outer space, primarily consisting of protons, electrons, alpha particles, and larger nuclei.
What is nuclear transmutation?
Answer: Nuclear transmutation is the spontaneous process in which an unstable parent nuclide changes into a more stable daughter nuclide with the emission of radiations during natural radioactivity.
How is alpha decay represented in a nuclear equation?
Answer: Alpha (α)-decay is represented by the general equation: parent nuclide → daughter nuclide + alpha-particle.
What happens to the atomic and nucleon numbers during alpha decay?
Answer: In alpha decay, the atomic number (Z) of the parent nuclide reduces by 2, and its nucleon number (A) decreases by 4.
How is beta decay represented in a nuclear equation?
Answer: Beta (β)-decay is represented by the general equation: parent nuclide → daughter nuclide + beta-particle.
What happens to the atomic and nucleon numbers during beta decay?
Answer: In beta decay, the atomic number (Z) of the parent nuclide increases by 1, while its nucleon number (A) remains unchanged.
What are gamma rays, and when are they usually emitted?
Answer: Gamma rays are fast-moving electromagnetic radiations emitted by unstable excited nuclei. They are usually emitted along with either an alpha or beta particle.
Which type of radiation has the greatest power of ionization?
Answer: Alpha particles have the greatest power of ionization among alpha, beta, and gamma radiations, due to their large positive charge and large mass.
Which type of radiation has the greatest penetrating power?
Answer: Gamma rays have the greatest penetrating power among alpha, beta, and gamma radiations, due to their large speed and neutral nature.
What is the process of radioactivity, and what is it proportional to?
Answer: The process of radioactivity is random, and the rate of radioactive decay is proportional to the number of unstable nuclei present.
What is the definition of half-life?
Answer: The half-life is the time during which half of the unstable radioactive nuclei in a sample disintegrate.
Does every radioactive element have its own specific half-life?
Answer: Yes, every radioactive element has its own characteristic half-life.
Give an example of a radioactive element and its half-life.
Answer: Radium-226 has a half-life of 1620 years.
What is the relationship between the number of atoms remaining and the number of half-lives that have passed?
Answer: The number of atoms remaining in a sample of a radioactive element after ‘t’ half-lives can be determined using the formula: Remaining atoms = Original atoms × (1/2)^t.
Is the process of radioactivity affected by chemical combinations, physical conditions, temperature, pressure, electric, or magnetic fields?
Answer: No, the process of radioactivity is not affected by chemical combinations or physical conditions like temperature, pressure, electric, or magnetic fields.
How is the half-life of a radioactive sample calculated?
Answer: The half-life can be determined by the time it takes for the activity of the sample to decrease to one-half of its original value.
Calculate the half-life of a radioactive bismuth sample based on the information given.
Answer: The half-life of the radioactive bismuth sample is 5 days.
How long will it take for the count rate of a radioactive element to drop to 250 counts per minute, given that its half-life is 40 minutes?
Answer: It will take 80 minutes for the count rate to drop to 250 counts per minute.
What precaution should be taken during radiation treatment to ensure the safety of healthy cells?
Answer: The beam of radiation should be directed only at cancerous cells to spare healthy cells.
What are stable nuclei?
Answer: Stable nuclei are nuclei that do not emit radiations naturally.
Which nuclei are generally stable with atomic numbers 1 to 82?
Answer: Nuclei with atomic numbers 1 to 82 are generally stable.
What happens to nuclei with atomic numbers greater than 82?
Answer: Nuclei with atomic numbers greater than 82 are naturally unstable and emit different types of radiations continuously.
How can stable and non-radioactive elements be changed into radioactive elements?
Answer: Stable and non-radioactive elements can be changed into radioactive elements by bombarding them with protons, neutrons, or alpha particles.
What are artificially produced radioactive elements called?
Answer: Artificially produced radioactive elements are called radioactive isotopes or radioisotopes.
What is the purpose of using radioactive tracers in medicine, industry, and agriculture?
Answer: Radioactive tracers are used to explore the metabolism of chemical reactions inside the human body, animals, or plants, as well as for locating wear and tear in machinery, and finding leaks in underground pipes. In agriculture, they help determine how well plants are absorbing essential nutrients.
How is radio iodine-131 used in medicine?
Answer: Radio iodine-131 is used to monitor thyroid functioning as it readily accumulates in the thyroid gland.
Which radioisotope is used for the diagnosis of brain tumors?
Answer: Phosphorous-32 is used for the diagnosis of brain tumors.
How are radioisotopes used in medical treatment?
Answer: Radioisotopes, like radioactive cobalt-60, are used in nuclear medicine to cure various diseases, such as cancerous tumors and cells. The radiations kill the cells of the malignant tumor in the patient.
What is the source of radioactive carbon-14 in the atmosphere?
Answer: Radioactive carbon-14 is produced in the atmosphere by cosmic rays interacting with nitrogen.
How do live plants become slightly radioactive?
Answer: Live plants become slightly radioactive by absorbing radioactive carbon dioxide from the atmosphere.
How is radiocarbon dating possible?
Answer: Radiocarbon dating is possible because plants and animals absorb radioactive carbon-14 through their intake of carbon dioxide. When a plant or animal dies, the carbon-14 inside it starts to decay, allowing scientists to estimate its age by comparing its carbon-14 activity with that of live organisms.
How is the age of a dead tree estimated using radiocarbon dating?
Answer: The age of a dead tree is estimated by comparing the activity of carbon-14 in the dead tree with that of a live tree. The half-life of carbon-14 is 5730 years, so the number of half-lives that have passed since the tree died gives its approximate age.
Apart from carbon-14, what other radioisotope is used to estimate the age of geological specimens?
Answer: Potassium-40 is another radioisotope used to estimate the age of geological specimens. It decays to the stable argon nuclide Ar-40 with a half-life of 2.4 × 10^8 years.
How is a nuclear fission reaction initiated?
Answer: Nuclear fission takes place when a heavy nucleus, such as uranium-235, absorbs a slow-moving neutron.
What is the consequence of an uncontrolled fission chain reaction?
Answer: An uncontrolled fission chain reaction can lead to a rapid and possibly explosive release of an enormous amount of energy.
How is a fission chain reaction controlled in nuclear reactors?
Answer: In nuclear reactors, the fission chain reaction is controlled by absorbing the extra neutrons liberated in fission reactions using some material to slow down the chain reaction.
What is nuclear fusion?
Answer: Nuclear fusion is a process where two light nuclei combine to form a heavier nucleus, releasing energy in the process.
What is the product of the fusion reaction between deuterium and tritium?
Answer: The product of the fusion reaction between deuterium and tritium is a helium nucleus (alpha particle) along with 25.7 MeV of energy.
What are some of the harmful effects on human beings due to radiations?
Answer: Radiation burns, sterility, genetic mutations, leukemia, blindness or cataract formation.
What are some of the uses of radioactive and nuclear materials?
Answer: Radioactive and nuclear materials are used in nuclear power plants, nuclear-powered submarines, intercontinental ballistic missiles, medicine, agriculture, and industry.
What caused the massive destruction during the nuclear accident at Chernobyl, Russia?
Answer: The explosion of the nuclear reactors, which melted through thick concrete housing, caused the massive destruction of the local community and contaminated vegetation and livestock in the large surrounding area.
How should radioactive sources be handled to ensure safety?
Answer: Radioactive sources should only be handled with tongs and forceps. The user should use rubber gloves, and hands should be carefully washed after the experiment. All radioactive sources should be stored in thick lead containers.
What precautions should be taken to avoid exposure to radiation-sensitive areas?
Answer: Frequent visits to radiation-sensitive areas should be avoided, and when handling radioactive sources, strict safety precautions should be followed.