Class 10 Physics Chapter 9 Question Answer

Important Class 10 Physics Chapter 9 Question Answer written by Honorable Mr. Qamar Jamal Suib. These computerized notes are very helpful in the preparation of Sound for students of the 10th class Physics and these are according to the paper patterns of all Punjab boards.

• Here are the detailed Class 10 Physics Chapter 9 Question Answer to help you prepare for your exams.
• Important Multiple Choice Questions (MCQs) with correct Answers of Chapter No. 18: Atomic and Nuclear Physics in Physics class 10th Urdu Medium.
• Important Short Questions with Correct Answers of Chapter No. 18: Atomic and Nuclear Physics in Physics class 10th Urdu Medium.
• NATURAL RADIOACTIVITY:
• In 1896, Becquerel accidentally discovered that uranium salt crystals emit an invisible radiation that can darken a photographic plate. He also observed that the radiation had the ability to ionize a gas. Subsequent experiments by other scientists showed that other substances also emited radiations. The most significant investigations of this type were conducted by Marie Curie and her husband Pierre. They discovered two new elements which emitted radiations. These were named polonium and radium. This process of emission of radiations by some elements was called natural radioactivity by Marie Curie. Subsequent experiments performed by Henrey Becquerel suggested that radioactivity was the result of the decay or disintegration of unstable nuclei.
• "The spontaneous emission of radiation by unstable nuclei is called natural radioactivity. And the elements which emit such radiations are called radioactive elements".
• Three types of radiation are usually emitted by a radioactive substance. They are: alpha particles; beta particles; and gamma rays. These three forms of radiations were studied by using the scheme. The radioactive source is placed inside the magnetic field. The radiation emitted from the source splits into three components: and radiations bend in opposite direction in the magnetic field while radiation does not change its direction. 
• BACKGROUND RADIATIONS:
• Radiations present in atmosphere due to different radioactive substances are called background radiations. Everywhere in rocks, soil, water, and air of our planet are traces of radioactive elements. This natural radiation is called the background radiation. It is as much part of our environment as sunshine and rain.
• If you're looking for comprehensive 10th class physics chapter 9 question answer, you've come to the right place.
• Fortunately, our bodies can tolerate it. Only places where radiation is very high can be injurious to health. The Earth, and all living things on it also receive radiation from outer space. This radiation is called cosmic radiation which primarily consists of protons, electrons, alpha particles and larger nuclei. The cosmic radiation interacts with atoms in the atmosphere to create a shower of secondary radiation, including X-rays, muons, protons, alpha particles, electrons, and neutrons.
• NUCLEAR TRANSMUTATIONS:
• We know that during natural radioactivity, an unstable nucleus of radioactive element disintegrates to become more stable.
• "The spontaneous process in which a parent unstable nuclide changes into a more stable daughter nuclide with the emission of radiations is called nuclear transmutation".
• Now we represent radioactive decay by means of a nuclear equation in which an unstable parent nuclide X changes into a daughter nuclide Y with the emission of an alpha particle, beta particle or gamma particle.
• Nature and Properties of Radiations:
• Alpha particle is a helium nucleus comprising of two protons and two neutrons with a charge of 2e. An unstable nucleus with large protons and neutrons may decay by emitting alpha radiations. . Beta radiation is a stream of high-energy electrons. An unstable nuclei with excess of neutrons may eject beta radiations. Gamma radiations are fast moving light photons. They are electromagnetic radiations of very high frequency (short wavelength) emitted by the unstable excited nuclie.
• Ionizing Effect:
• The phenomenon by which radiations split matter into positive and negative ions is called ionization. All three kinds of radiations i.e., alpha, beta and gamma can ionize the matter. However, alpha particles have the greatest power of ionization as compared to beta particles and gamma rays. It is due to large positive charge and large mass of alpha particles. Beta particles ionize a gas much less than alpha particles. The ionization power of gamma rays is even less than that of beta particles. Ionization of three radiations in a gas.