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CCE Model Exercises, , Improv, e Your 5, ys Learning (Text. P. No. 134), , I. Co, - Conceptu: :, if oan ptual Understanding (AS!), e followin A —, @) Aptasticecal: g cannot be charged easily by friction ? ’, (b) Acopper rod “, (c) An inflated balloon, (d) A woollen cloth, (e) Piece of wood, —Whena : ., 2 i asl glass rod is rubbed with a piece of silk cloth the rod, an the cloth both acquire positive charge. ( b), (b) becomes positively charged while the cloth has a negative charge., (c) and the cloth both acquire negative charge., (d) pocmaes negatively charged while the cloth has a positive charge., (3. Identify True or False sentences among the following:, (a) Like charges attract each other (T/F), , A. False, (b) A charged glass rod attracts a charged plastic straw (1/F), A., , 4, , True, (c) Lightning, A. False, (d) Earthquake:, A, False /, Sometimes; a crackling sound is heard while taking off sweater, during winter. Explain., A. During the process, and the fibres of the, , on our body. These ar, is an electrical conductor,, , conductor can not protect a building from lightning (1/F), , s can be predicted in advance (T/F), , of taking off sweater rubbing takes place between our body, , sweater. Static charges develop on the, e opposite charges. In presence of moisture (winter), which, , discharge takes place between the two opposite, , as sounds are produced., , sweater as well as, , , , - 1, es. Then sparks as wel : \ ie, 5 bran whyacha rged body losesits charge if wetouch itwith our hand., d i Fie we touch a charged object, it loses charge to the earth through our, A., body- ad fi the object he is ;:, 2 Thus: charge is transferred from ne object to the earth. This process is, ai saa : 215 9. Some Natural Phenomena, ica’, 3 vr phy (ono SM rae

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_ 8 Name the scale on which the destructive energy,of an earthquake is, , measured. An earthquake measures 3 on this scale. Would it be, , recorded by a seismograph? Is it likely to cause much damage ?, A. 1), , The power of an earthquake is measured on Richter scale. It is not a linear, scale. It is a logarithmic scale., , 2) Yes, it would be recorded by a seismograph., , 3) But itis not likely to cause much damage., , _1. Suggest three measures to protect ourselves.from lightning., , A. 1) Ahouse ora building of a low height is a safe place., , 2) Ifyouare travelling in a bus or in a car, close the doors and windows. Then, , you are safe inside that vehicle., , ', , mi _lf you are ina forest, take shelter under short trees. Then you are safe., Explain why a charged balloon is repelled by another charged balloon, whereas an uncharged balloon is attracted by a charged balloon ?, A. [5)-* charged balloon is repelled by another charged balloon., Reason : The same type of electric charge is present on both the balloons., We know, "like charges repel each other." So the two balloons with like charges, on them, repel each other., _B)-An uncharged balloon is attracted by a charged balloon., Reason : We know, "if a charged body is brought nearer to an uncharged, , body, an equal and opposite charge appears on that body." This process is, called, 'induction'., , In the present case, when the uncharged balloon is brought nearer the, , charged balloon, an equal and opposite charge is induced on that balloon., We know, ‘unlike charges attract each other'. So now, the two balloons, carrying opposite charges, attract each other., [ The a principle in this activity’ is that, 'induction preceeds, attraction’. }, \ three states in India where earthquakes are more likely to occure., A. 1) Kashmir 2) Rajasthan 3) Gujarat, , , , Physical Science - 8 216 9. Some Natural Phenomena, $73 8th Phy (EM) $M Finals

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a, , soCBees your habitation li, Bbitauen lie in a earthquake prone area? explain, y, / A. Yes., , A. InAnd 5], ndhra Pradesh, Ongole and its near-by places expe!, , 1, , A. 1) When matter gains electric charges or los, , 13. at happens if two o!, , A.A) When two objects ca, , 1) Ilivei i, ‘ a . Krishna district, Andhra Pradesh, ‘ording to seismi re, hn g to. seismic hazard map, Andhra Pradesh lies in seisnu', a aa district lies in zone III, ich place i, place in Andhra Pradesh experiences earthquake, , the times?, rienced earthquakes most, , 7on Richter, , ic zones Il, , s most of, , of the ti i ., mes. The intensity of these earthquakes lie between 5 and, , scale., , he é i, n does a piece of matter have a “charge ”, es them, it'ac, , place between two material, , quires a chargeIs, when, , 27° Transfer of electric charges is likely to take, they are rubbed together., 3) Thus matter gets charged, when electric charg, , es are transferred from one, , body to another., 4 The process by whic!, , electrification’., are brought close, nt charges, , ha body gets charged is called ', , bjects having same charge, ns if two objects having differe:, , ve an example for this ?, , rrying the same type of charge are brought closer to, , each other, they repel each other (Like charges repel each other)., , LY?) ‘When two objects carrying opposite charges are brought closer to each other,, they attract each other. (Unlike charges attract each other)., , to each other? What happe!, are brought close 2.Can you gi, , Examples:, rod is rubbed with a piece of silk cloth, glass rod gets +vely, , D When a glass, charged, and the silk cloth, - vely charged., astic straw is rubbed with a polythe:, straw, - vely charged., , A When a pl, + vely charged, and the plastic, ary charged) near the piece of the polythene sheet, , 3) Bring the Blass T°, ). They repel each other (two tve charges repel each other), charged) near the plastic straw (-vely charged)., , (-vely charged, ther (opposite charges attract each other.), , 217, 9. Some Natural Phenomena, , ne sheet, polythene sheet gets

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14. Give two examples of effects in your daily which are caused by |, a ‘transfer of charges., A. ‘Transfer of charge' takes place at least in two instances. They are ;, 1) during lightning and, 2) during earthing, , 1) During lightning, we should not speak with landline telephone. It may give, a fatal electric shock., , 2) While meddling with any electrical installation in our house, if by chance,, we happen to touch a live wire, immediately we experience a fatal electric, shock. This is due to the ‘earthing’ of the electricity., , Ill. Expermentation and field investigation (AS3), 15<“Inflate two balloons and rub both of them with a cloth first and then, with different material. Will they attract each other in both cases ?, , A. 1) Inboth the cases, the balloons acquire the same type of charge., 2) Since ‘like charges repel, the balloons repel each other, in both the cases., , TV. Information Skills and Project (AS4), , 46 Yoh country in the world is frequently affected by earth quakes?, Collect the information and photographs on recently occurred, earthquake in Japan., , ok Japan, 2011 Japan Earthquake and Tsunami :, , Earthquakes and tsunamis are among the most frightening natural, phenomena. If a severe earthquake or tsunami occurs in a densely populated, area, it can practically swallow the city. This is what recently happened in Japan., , On March 11, 2011, an 8.9 magnitude earthquake hit off the east coast of, Japan, followed by a disastrous tsunami. It was the largest ever earthquake in, areas of the Japan's recorded history. Houses, cars and much else were washed, , away by high tsunami waves. There has been a massive power failure in many, , , , areas of the country., Japanese officials confirmed that radioactive materials have leaked into the, atmosphere, following a fire at reactor number 4 at the Fukushima power plant. a, , Here are some of the images from Japan after the ferocious tsunami and, , Seanirnisese, , , , earthquake hit, causing many injuries, fires and massive disaster,, , , , Physical Science - 8 218 9. Some Natural Phenomena, 573 8th Phy (LM) SM Finats

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A fishi : !, shing boat is noticeably out of place after being swept ashore during the, , massive tsunami., , , , , , Find out if there is an organisation in your area which provides relief, , to those suffering from natural disaster. Enquire about the type of, , help they render to the victims of earthquakes. Prepare a brief report, on the problems of the earthquake victims., , A. Our state is less prone to earthquakes. However, cyclones cause natural disasters., , 1) In our area Red Cross Society, RSS and other charitable societies provide, , ’ relief in natural disasters., 2) They render different services like providing shelter, clothing and medicinal, , help., ake victims generally face the problems of health hazards, damaged, , 3) Earthq 1, houses, crop damages, poor sanitation, lack of drinking facility and unhygienic, , conditions., , 487 How do you re, lines during ea, , late the energy release during the colluision of fault, rthquake to the atmospheric variation on the surface, , , , of the earth ?, A. After occuring earthquakes, there are changes in atmospheric temperature, and humidity; 219), Physical Science ~ 8 USaMANAL A eacmann, , ‘573 8th Phy (END SM Finals. +