{"id":4091,"date":"2023-10-06T09:35:10","date_gmt":"2023-10-06T09:35:10","guid":{"rendered":"http:\/\/localhost\/ecole9ja\/?p=4091"},"modified":"2023-10-06T09:38:58","modified_gmt":"2023-10-06T09:38:58","slug":"week-4-ss3-second-term-physics-notes","status":"publish","type":"post","link":"https:\/\/ecolebooks.com\/nigeria\/posts\/week-4-ss3-second-term-physics-notes\/","title":{"rendered":"Week 4 &#8211; SS3 Second Term Physics Notes"},"content":{"rendered":"<p>\u00a0<strong>WEEK FOUR<br \/>\n<\/strong><strong>TOPIC: RADIOACTIVITY (1)<br \/>\n<\/strong><strong>CONTENTS<br \/>\n<\/strong><\/p>\n<ul>\n<li>Emission of Alpha and Beta particles and Gamma rays\n<\/li>\n<li>Properties and peaceful uses of radioactivity\n<\/li>\n<li>Radioactive hazards and safety precautions\n<\/li>\n<li>Binding energy<strong><br \/>\n\t\t\t<\/strong><\/li>\n<\/ul>\n<p>\u00a0Radioactivity is the spontaneous decay or disintegration of  the nucleus of the atom of an element during which it emits \u03b1, \u03b2 or \u03b3 rays or a combination of any or all the three and energy ( or heat).<\/p>\n<p>\u00a0If a small sample of radium is placed at the bottom of a small hole drilled in a block of lead.  The radiation emitted from this radium emerged from the hole in a narrow beam. if  the rays were subjected to a strong magnetic field placed at the side of a beam. A photographic plate situated at appropriate sides to receive the rays showed that the paths of some rays were bent to the right, some to the left and some went straight on, unbent.<\/p>\n<p>\u00a0Electrically charged plates placed at the side of the beam gave the same effect.  The radiations that was bent towards the negative electric plate or the south pole of the magnetic field are called the Alpha particles ( \u03b1 \u2013particles ) <\/p>\n<p>\u00a0The radiations deflected towards the positive electric plate or the North pole of the magnetic field is called Beta particles (\u03b2 \u2013 particles ). The radiation that was neither affected by the electric or magnetic field is called gamma rays (\u03b3 ). They are actually electromagnetic radiations.<\/p>\n<div>\n<table>\n<tbody>\n<tr>\n<td>Radiation\u00a0<\/td>\n<td>Alpha-particles\u00a0<\/td>\n<td>Beta Particles\u00a0<\/td>\n<td>Gamma &#8211; rays\u00a0<\/td>\n<\/tr>\n<tr>\n<td>Nature\u00a0<\/td>\n<td>Helium nuclei <sup>4<\/sup><sub>2<\/sub>He<\/td>\n<td>High Energy electrons\u00a0<\/td>\n<td>Electromagnetic wave of short wavelength\u00a0<\/td>\n<\/tr>\n<tr>\n<td>Velocity<\/td>\n<td> 5 \u2013 7% speed of light<\/td>\n<td>Travel at approx. speed of light<\/td>\n<td>Travel at speed of light<\/td>\n<\/tr>\n<tr>\n<td>Effects of magnetic field<\/td>\n<td>Slightly deflected in a magnetic field (+ve)<\/td>\n<td>Strongly deflected in a magnetic field (-ve)<\/td>\n<td>No effects<\/td>\n<\/tr>\n<tr>\n<td>Ionizing magnetic field<\/td>\n<td>Large, cause heavy ionization<\/td>\n<td>Medium<\/td>\n<td>Small<\/td>\n<\/tr>\n<tr>\n<td>Penetrating power<\/td>\n<td>Little penetrating power e.g thin sheet<\/td>\n<td>Good penetrating power e.g aluminium<\/td>\n<td>High penetrating power e.g leads<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>Radioactive Decay; Half-life, Decay Constant<\/p>\n<p>\u00a0Radioactivity is a spontaneous process. It goes on independent of external control, it is not affected by temperature, or pressure or by chemical treatment. It is a random process as no one can predict which atom will disintegrate at a given time.<strong><br \/>\n\t\t<\/strong><strong>The half-life of a radioactive element is the time taken for half of the atoms initially present in the element to decay.<\/strong>  The rate of decay of radioactive elements is found to be proportional to the number of atoms of the material present.  If there are N atoms of a radioactive element present at a time, ti, then the probable number of disintegration per unit time or activity.<br \/>\n\u00a0\u00a0\u00a0\u00a0N \u03b1   &#8211;   dN<br \/>\n                         Dt<br \/>\nThe minus sign arises from the fact that N is decreasing with time<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0dN   = -\u03bbN<br \/>\n                         dt<br \/>\n\u03bb is a constant of proportionality called the decay constant.<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se1.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0:.  \u03bb  =  &#8211;  1<br \/>\n\t\tdN<br \/>\n\t                           N               dt<br \/>\nHence, decay constant is defined as the instantaneous rate of decay per unit atom of a substance<br \/>\n \u039b =  No of atoms disintegrating per second<br \/>\n        Np pf atoms in the source at that time<\/p>\n<p>\u00a0By integration<br \/>\n\u00a0\u00a0\u00a0\u00a0N =Noe<sup>-\u03bbt<\/sup><br \/>\n\tNo = Number of atoms present at time t = o<br \/>\nN = Number of atoms present at time t<br \/>\nT  =  0.693<br \/>\n            \u039b<\/p>\n<p>\u00a0<br \/>\n\u00a0<img decoding=\"async\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se2.png\" alt=\"\"\/><br \/>\n\tExample<br \/>\nA certain radioactive element has a half-life of 10years.<\/p>\n<ol>\n<li>How long will take to lose 7\/8 of its atoms originally present.\n<\/li>\n<li>How long will it take until only \u00bc of the atoms originally present remain unchanged.\n<\/li>\n<\/ol>\n<p>\u00a0If 7\/8 of its atoms has been lost, 1\/8 remains<br \/>\n  Half-life = 10years<br \/>\n  N\/4 remains after 20 years<br \/>\nN\/8 remains after 30 years:. it takes 30 years to lose 7\/8 of its atoms<br \/>\nN\/2  remain unchanged after 10 years<br \/>\nN\/4 remains unchanged after 20 years<br \/>\nAns = 20years<\/p>\n<p>\u00a0<strong>EVALUATION<\/strong><br \/>\n\tIf the half life of a radioactive substance is 2.45 X 10<sup>8<\/sup>s, determine is decay constant. <\/p>\n<p>\u00a0<strong>TRANSFORMATION OF ELEMENTS<br \/>\n<\/strong>There are two types of radioactivity<\/p>\n<ol>\n<li>Natural  radioactivity\n<\/li>\n<li>Artificial radioactivity<strong><br \/>\n\t\t\t<\/strong><\/li>\n<\/ol>\n<p>\u00a0<strong>Natural  radioactivity is the spontaneous disintegration of the nucleus of an atom during which \u03b1 particles,\u03b2 particles or \u03b3 rays and heat ( or energy) are released<\/strong>. When a radioactive elements undergoes radioactive decay, it may emit either \u03b1 ,<em>B,<\/em> or \u03b3 rays. This changes the atomic number of the element, hence a new element is formed.<\/p>\n<p>\t\t<sup>226<\/sup><br \/>\n\t\t<sub>88<\/sub>X        \u03b1\u00a0\u00a0\u00a0\u00a0            <sup>4<\/sup><sub>2<\/sub>He + <sup>222<\/sup><sub>86<\/sub>Rn   + energy<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se3.png\" alt=\"\"\/><br \/>\n\t<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se4.png\" alt=\"\"\/><sup>222<\/sup><sub>88<\/sub>            2<em>B<\/em>              2 <sup>0<\/sup><sub>-1<\/sub>e  + <sup>222<\/sup><sub>90<\/sub>Ra  + energy<\/p>\n<p>\u00a0<sup>238<\/sup>  U       2\u03b1, 2\u03b2        2 ( <sup>4<\/sup><sub>2<\/sub>He) +  2 <sub>-1<\/sub><sup>o<\/sup>e  + <sup>230<\/sup> Th + energy<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se5.png\" alt=\"\"\/><br \/>\n\t\t<sub>92<\/sub><br \/>\n\t\t<sub> 91<\/sub><\/p>\n<p>\u00a0<sup>234<\/sup> U          \u03b2<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se6.png\" alt=\"\"\/><br \/>\n\t\t<sub>90<\/sub><br \/>\n\t\t<sup>0<\/sup><sub>-1<\/sub>e  + <sup>234<\/sup><sub>91<\/sub>Pa + energy<\/p>\n<p>\u00a0Generally we represent alpha (\u03b1) decay by<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se7.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se8.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se9.png\" alt=\"\"\/>A\u00a0\u00a0\u00a0\u00a0<sup>4<\/sup><sub>2<\/sub> He +  <sup>A  &#8211; 4<\/sup>    y  + energy<br \/>\nZ                                                <sub>Z  &#8211; 2<\/sub><\/p>\n<p>\u00a0And  <em>B<\/em> decay by<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se10.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se11.png\" alt=\"\"\/>A<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se12.png\" alt=\"\"\/>Z\u00a0\u00a0\u00a0\u00a0<sup>0<\/sup><sub>-1 <\/sub>e  + A y<br \/>\n                                             (z+1)<\/p>\n<p>\u00a0<strong>ARTIFICIAL RADIOACTIVITY<br \/>\n<\/strong>If the  radioactivity is induced in an element by irradiation with for neutrons, the process is known as artificial radioactivity.  By irradiation, it means exposure to radiation either by accident or by intent.<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se13.png\" alt=\"\"\/><sup>4<\/sup><br \/>\n\t\t<sub>2<\/sub>He  + <sup>14 <\/sup><sub>7<\/sub>N                         <sup>18<\/sup><br \/>\n\t\t<sub>9<\/sub>F   <sup>17<\/sup><br \/>\n\t\t<sub>8<\/sub>O  +  <sup>1<\/sup><br \/>\n\t\t<sub>1<\/sub>H  + energy<br \/>\nin artificial radioactivity, an ordinary materials is made radioactive by bombarding itwith radioactive particles.<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se14.png\" alt=\"\"\/><sup>4<\/sup>He +<sup> 27<\/sup> Al \u00a0\u00a0\u00a0\u00a0<sup>30<\/sup>P + <sup>1<\/sup>n<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se15.png\" alt=\"\"\/><sup>1<\/sup><sub>0 <\/sub>n + <sup>6<\/sup><sub>3<\/sub>Li        <sup>3<\/sup><sub>1<\/sub>H  + <sup>4<\/sup><sub>2<\/sub>He + energy<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se16.png\" alt=\"\"\/><sup>1<\/sup><sub>0<\/sub> n  + <sup>24<\/sup><sub>12<\/sub>Mg          <sup>24<\/sup><sub>11<\/sub>Na  + <sup>1<\/sup><sub>1<\/sub>P + energy<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se17.png\" alt=\"\"\/><sup>4<\/sup><sub>2<\/sub>He + <sup>9<\/sup><sub>4<\/sub>Be            <sup>12<\/sup><sub>6<\/sub>C + <sup>1<\/sup><sub>0<\/sub>n + energy<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se18.png\" alt=\"\"\/><sup>1<\/sup><sub>0<\/sub>n  +<sup>59<\/sup><sub>27<\/sub>Co            <sup>60<\/sup><sub>27<\/sub>Co + energy<br \/>\nIsotopes can also be made artificially by bombarding neutrons, or protons or deuterons at elements e.g.<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se19.png\" alt=\"\"\/><sup>34<\/sup><sub>10<\/sub>S  + <sup>1<\/sup><sub>0<\/sub>n \u00a0\u00a0\u00a0\u00a0<sup>35<\/sup><sub>10<\/sub>S + energy<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100623_0935_Week4SS3Se20.png\" alt=\"\"\/><sup>79<\/sup><sub>10<\/sub>Br   + <sup>1<\/sup><sub>0<\/sub>n          <sup>35<\/sup><sub>10<\/sub>Br + energy<br \/>\nsuch artificially produced isotope are unstable and decay with the  emission of \u03b1 \u2013 particles, \u03b2 \u2013particles and \u03b3 \u2013 rays. They are called radio isotopes.<\/p>\n<p>\u00a0<strong>GENERAL EVALUATION<\/strong><\/p>\n<ol>\n<li>With the aid of a diagram, explain the anomalous behaviour of water\n<\/li>\n<li>Describe an experiment to determine the apparent cubic expansivity of a liquid\n<\/li>\n<\/ol>\n<p>\u00a0<strong>READING ASSIGNMENT<\/strong><br \/>\n\tNew School Physics pg 468-471<\/p>\n<p>\u00a0<strong>WEEKEND ASSIGNMENT<br \/>\n<\/strong>1.\u00a0\u00a0\u00a0\u00a0The phenomemon of radioactivity was first discovered by (A) Marie  Curie   (B) J.J. Thompson    (C) Henri Becquerel  (D) Nent Bohr (E) Enrico Fermi<br \/>\n2. \u00a0\u00a0\u00a0\u00a0A radioactive substance has a half-life of 3 days. If a mass of 1.55g of this substance is left after decaying for 15days,dertermine the original value of the mass (A) 49.6g\u00a0\u00a0\u00a0\u00a0(B) 37.2g   (C) 24.8g   (D) 12.4g<br \/>\n3.  \u00a0\u00a0\u00a0\u00a0Which of the following is usually used to cause fission in an atomic reactor? (A) alpha particles    (B) beta particles  (C ) electrons  (D) neutrons<br \/>\n4.  \u00a0\u00a0\u00a0\u00a0A substance has a half-life 30 mins after 6mins the count rate was observed to be 400. What was its count rate at zero time. (A) 200 (B) 1200   (C) 1600 (D) 2400<br \/>\n5. \u00a0\u00a0\u00a0\u00a0A nuclide  <sup>202<\/sup><sub>84<\/sub>Y emits in succession an \u03b1-particle and \u03b2-particle. The atomic number of the resulting nuclide is (A) 198         (B) 83        (C  ) 82     (D) 80.<\/p>\n<p>\u00a0<strong>THEORY<\/strong><br \/>\n\t1\u00a0\u00a0\u00a0\u00a0(a) Define radioactivity; half-life and decay constant.<br \/>\n(b) Write down the relation between half-life and decay constant<br \/>\n(c) In 180 minutes, the activity of a certain radioactive substance falls to one \u2013eight of its original value. Calculate its half-life.<br \/>\n2\u00a0\u00a0\u00a0\u00a0(a)A nuclide X emits \u03b2-particle to form a daughter nuclide Y. write a nuclear equation to illustrate the charge conservation.<br \/>\n(b) the isotope of a nuclide has a half-life of 5.4X10<sup>3<\/sup>s.Calculate its decay constant.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u00a0WEEK FOUR TOPIC: RADIOACTIVITY (1) CONTENTS Emission of Alpha and Beta particles and Gamma rays&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,317],"tags":[],"class_list":["post-4091","post","type-post","status-publish","format-standard","hentry","category-posts","category-second-term-ss3-physics"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/4091","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/comments?post=4091"}],"version-history":[{"count":1,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/4091\/revisions"}],"predecessor-version":[{"id":4092,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/4091\/revisions\/4092"}],"wp:attachment":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/media?parent=4091"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/categories?post=4091"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/tags?post=4091"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}