雅思阅读练习题:Global warming

雅思阅读练习题:Global warming
雅思阅读练习题:Global warming

雅思阅读练习题:Global warming

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Global warming

You should spend about 20 minutes on Questions 1-13 which are based on Reading Passage 1 below.

Questions 1-5 Reading Passage 1 has six paragraphs A-F .

Choose the most suitable headings for paragraphs B-F from the list of headings below.

Write the appropriate numbers i-viii in boxes 1 - 5 on your answer sheet.

List of Headings

i The plaintiffs?viewpoints on regulating emission

ii Federal government being taken to court

iii Possible impact of the case on other lawsuits

iv Regulating air pollution by twelve States

v Stance of the Bush administration

vi Viewpoints of Bill Clinton on regulation

vii The call for emission caps and reduction

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viii Uncertainty in ruling by the Supreme Court

Example Answer

Paragraph A ii

1. Paragraph B _____

2. Paragraph C _____

3. Paragraph D_____

4. Paragraph E _____

5. Paragraph F _____

Green states take the federal government to court

Nov 30th 2006

From The Economist print edition

A WHEN the subject is global warming,the villain is usually America . Although it produces a quarter of the greenhouse gases that are heating up the planet,it refuses to regulate them. When other countries agreed on an international treaty to do so——he Kyoto protocol——America failed to ratify it. But not all American officialdom is happy with the federal government's stance. In fact,12 states disagree so fiercely that they are suing to force it to curb emissions of carbon dioxide,the most common greenhouse gas. The Supreme Court heard argument in the case on November 29th. The outcome will not be known for months,but the political wind seems to be shifting in favour of firmer action to

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counter climate change.

B The Clean Air Act charges the Environmental Protection Agency (EPA) with regulating air pollution from vehicles. But the EPA argues that Congress did not intend to include CO2 under that heading,and that to do so would extend the EPA's authority to an unreasonable extent. Furthermore,it contends that regulating emissions would not do good unless all or most other countries did the same. That is in keeping with the policies of President George Bush,who opposes mandatory curbs on emissions and believes that any international accord on global warming should apply to all countries——unlike the Kyoto protocol,which exempts poor ones,including big polluters such as China and India . Ten states,among them gas-guzzling Texas and car-making Michigan,also back the EPA.

C The plaintiffs comprise 12 states,three cities,various NGOs,and American Samoa,a Pacific territory in danger of vanishing beneath the rising ocean. They are supported by a further six states,two power companies,a ski resort,and assorted clergymen,Indian tribes and agitated grandees such as Madeleine Albright,a former secretary of state. They point out that under the administration of Bill Clinton,the EPA decided that it did have the authority to regulate CO2. The act,they note,says the EPA should regulate any air pollutant that "may reasonably

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be interpreted to endanger public health or welfare". It goes on to define public welfare to include "effects on soils,water,crops,vegetation,manmade materials,animals,wildlife,weather,visibility,and climate".

D The Supreme Court may give a mixed ruling,decreeing that carbon dioxide is indeed a pollutant,but one the EPA is free to ignore or regulate as it pleases. Or it might dismiss the complaint on the grounds that the plaintiffs did not have the right to lodge it in the first place. In theory,they must prove that the EPA's foot-dragging has caused them some specific harm that regulation might remedy——a tall order in a field as fraught with uncertainty as climatology. Even if the court found in the plaintiffs' favour,rapid change is unlikely. By the time the EPA had implemented such a ruling,Congress would probably have superseded it with a new law.

E That is the point,environmental groups say. They want Congress to pass a law tackling global warming,and hope that a favourable court ruling will jolly the politicians along. Moreover,the case has a bearing on several other bitterly-contested lawsuits. Carmakers,for example,are trying to get the courts to strike down a Californian state law based on certain provisions of the Clean Air Act that require them to reduce their vehicles' CO2 emissions. If the Supreme Court decides that the act does not apply to CO2,then the Californian law would also be in jeopardy.

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That,in turn,would scupper the decision of ten other states to adopt the same standard.

F However the Supreme Court rules,many state governments are determined to tackle climate change. California is in the vanguard. Its legislature has passed a law that will cap and then reduce industrial emissions of greenhouse gases. Seven eastern states have formed the Regional Greenhouse Gas Initiative,which will treat emissions from power plants the same way. Almost 400 mayors have signed an agreement to cut their cities' emissions in line with Kyoto. Many businesses,even some power companies,would rather see regulation now than prolonged uncertainty. And several of the leading contenders for 2008's presidential election are much keener on emissions caps than Mr Bush. Change is in the air.

Questions 6-9 Do the following statements reflect the views of the writer in the reading passage?

In boxes 6 - 9 on your answer sheet write

YES if the statement reflects the views of the writer

NO if the statement contradicts the views of the writer

NOT GIVEN if there is no information about this in the passage

6. Texas and Michigan are among the 12 states which call for regulating air pollution.

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7. An American island is in danger of disappearing beneath the rising ocean.

8. The plaintiffs can prove that the EPA foot-dragging has caused them harm that the regulation might remedy.

9. The Supreme Court's ruling may influence the results of other lawsuits.

Questions 10-13 Answer the following questions with NO MORE THAN THREE WORDS each in boxes 10 - 13.

10. What country produces 25% of the world's greenhouse gases?

11. Which president opposes mandatory curbs on emission,George Bush or Bill Clinton?

12. Who are trying to get the courts to strike down a Californian state law that require them to reduce their vehicles' CO2 emissions?

13. What would some power companies rather see than prolonged uncertainty at present?

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unit4globalwarming单词和句型重点总结

Unit 4 Global warming全球变暖 一、词汇 about发生;造成 注意:(1)come about是不及物动词短语,不能用于被动语态,常指情况不受人控制的突然发生。有时用it作形式主语,that从句作真正主语。 (2)表示“发生”的词或短语有:happen,occur,take place,break ① Many a quarrel comes about through a misunderstanding. ② The moon came out from behind the clouds. ③ I’ll let you know if anything comes up. ④ I’ll come over and see how you are coming along. ⑤ I came across an old friend yesterday. ⑥ When she came to, she couldn’t recognize the surroundings. ① I subscribe to your suggestion. ② Which magazine do you subscribe to? ③ He subscribed his name to the paper(文件). ④ He subscribed a large sum to the poor students. n.量;数量

① It’s cheaper to buy goods in quantity / in large quantities. ② A large quantity of silk is sold in Japan. ③ A large quantity of drugs are found in his home. ④ Large quantities of rain are needed in this area. ① He tends to get angry when others disagree with her. ② His views tend towards the extreme(极端). ③ He was tending (to) his son when I saw him in the hospital. ④ Jane is nice but has a tendency to talk too much. =Jane is nice but she tends to talk too much. ① The price of the new house in our area has gone up by 1,000 yuan per square meter(平方米)。That is(也就是说)it has gone up to 5,000 yuan per square meter. ② The wind has gone down a little. ④ The country has gone through too many wars.

初二物理平面镜成像知识点

初二物理平面镜成像知识点 初二物理平面镜成像知识点 1、光的反射类型:镜面反射(光滑表面、反光、刺眼)、漫反射(粗糙表面、各个方向) 注:1、镜面反射和漫反射均遵循光的反射定律;2、光反射时, 光路可逆 2、平面镜成像: (1)、平面镜成像的原理:光的反射定律。平面镜就是平时我们 用的镜子。 (2)、观察下图,平面镜成像的特点:等大(大小相同)、等距(离平面镜距离相等)、垂直(垂直于平面镜的底边)、正立(原来的样子)、虚像(不存在的像)。 注:在光学中涉及到的像可分成实像和虚像。它们的共同点是都能被人眼观察到,即都有光线射入人眼。它们的不同点是:实像可 以成在光屏上,如小孔成像,照像机成像、幻灯机成像均是实像;而 平面镜成像,放大镜成像均是虚像。实像是光线的实际会聚而成, 而虚像则是由发散的反射光线或折射光线的反向延长线会聚,形成 虚像。观察右图: (1)平面镜成的像和物体等大。 (2)像和物到平面镜的距离相等。 (3)像与物的连线与平面镜垂直。 (4)平面镜成的是正立的虚像。 (3)、平面镜的作用:(1)成像(2)改变光的传播方向(潜望镜)

3、用垂直等距和光路图找物体的像。光路图的画法。 画图中的实线和虚线: (1)实际光线用实线画,加箭头表示光线的行进方向; (2)反向延长线不是实际光线,所以用虚线画,不加箭头; (3)实像用实线画,虚像用虚线画,都要加箭头表示像的正倒; (4)法线等辅助线要用虚线画。 4、球面镜 凹面镜:(1)作用:会聚光线(2)应用:太阳灶、汽车头灯 凸面镜:(1)作用:发散光线(2)应用:汽车后视镜 5、虚像和实像 虚像:非实际光线而是光线的反向沿长线会聚而成的像。 实像:实际光线会聚而成的像叫实像。 在光学中涉及到的像可分成实像和虚像。它们的共同点是都能被人眼观察到,即都有光线射入人眼。它们的不同点是:实像可以成 在光屏上,如小孔成像,照像机成像、幻灯机成像均是实像;而平面 镜成像,放大镜成像均是虚像。实像是光线的实际会聚而成,而虚 像则是由发散的反射光线或折射光线的反向延长线会聚,形成虚像。 6、凸面镜和凹面镜 (1)用球面的外表面作为反射面的叫做凸面镜,用球面的内表面 作为反射面的叫做凹面镜。 (2)凸面镜对光有发散作用,凹面镜对光有汇聚作用。 (3)凸面镜和凹面镜都遵循光的反射定律。 (4)凸面镜成缩小的像,能扩大视野范围。

高中英语《Unit4Globalwarming》课文语法填空新人教版

《Unit 4 Global warming》 Does It Matter? 一、语法填空(根据课文内容、依据语法规则完成下面短文) When 1________ (compare) with most natural changes, that the temperature of the earth rose about one degree Fahrenheit during the 20th century is quite shocking. And it’s human activity 2________ has caused this global warming rather 3________ a random but natural phenomenon. Dr. Janice Foster explains that we add huge 4________ of extra carbon dioxide into the atmosphere by burning fossil 5________. From the second 6________ and the discovery of Charles Keeling, all scientists believe that the burning of more and more fossil fuels 7________ (result) in the increase in carbon dioxide. Greenhouse gases continue to build up. On the one hand, Dr. Foster thinks that the trend would be a 8________. On the other hand, George Hambley 9________ (state) that more carbon dioxide would encourage a greater range of animals and bring us 10________ better life.

初二物理光学知识点梳理

初中光学 1.通过对学生观察\注意力的有效训练,促使学生集中精神学习,激发学生观察的主动性2.通过主动探究的学习,提高学生的独立\主动性,培养学生独立完成任务的意识 3.通过动力观察法,提升学生自我认知能力,引导学生掌握光学的方法及技巧

iii.反射光线、入射光线和法线在同一平面(三线共面); iv.反射光线和入射光线分别位于法线两侧(两线分居); v.反射角等于入射角(两角相等)。 (3)光路可逆 i.当光线的传播方向反向时,它的传播路径不变,说明光路是可逆的。 ii.入射角增大,反射角随之增大;入射角减小,反射角随之减小 (4)镜面反射和漫反射 i.镜面反射:光滑镜面的反射叫镜面反射 ii.漫反射:平行光射到凹凸不平的平面上,反射光向着不同方向的反射叫漫反射 iii.镜面反射和漫反射都遵循光的反射定律。 (5)光的反射的应用 i.室内采光:假如在一个很大的大厅内,不想采用人工光源,可利用光的反射原理让大厅内获得 明亮而柔和的自然光。 ii.光导纤维:1870年,英国物理学奖丁达尔在一次实验中发现,光线能沿着弯曲的水流传播。 iii.角反射器:自行车尾部的黄色会反光的塑料灯,本身不能发光,但当晚上有灯照到上面的时候,它就能发出光,原因是那个塑料灯就是角反射器,将光沿原方向反射回去了,从而保证夜晚不 会被后面的车因看不到而撞到。 3. 平面镜成像 (1)平面镜成像的特点 i.像到平面镜的距离与物体到平面镜的距离的关系? ii.像与物体的大小关系?像与物体的连线与平面镜是否垂直? iii.平面镜成的是虚像还是实像? (2)平面镜成像的应用 i.平面镜能够成像; ii.平面镜可以改变光的传播方向:潜望镜 iii.利用平面镜成像增大空间 (3)凸面镜与凹面镜 i.凸面镜对光线有发散作用:弯道观察镜;汽车观后镜 ii.凹面镜对光线有会聚作用:手电筒,汽车灯,探照灯的反光装置 4.光的折射定义:光从一种介质斜射入另一种介质时,传播方向发生偏折的现象。 (光从一种介质垂直入射到另一种介质时,传播方向。) ;(三线共面)规律;(两线分居)当光从空气斜射入水或其它介质中时,折射角入射角。 在光的折射中,光路是的。 常见的光的折射现象:池水变浅、钢笔错位、海市蜃楼等

2021学年八年级物理上册4.3平面镜成像知识点与考点解析人教版.docx

4.3平面镜成像 一、平面镜成像 1. 平面镜成像利用的是光的反射。成像规律是:(1)像与物大小相等;(2)像到镜的距离与物到镜的距离相等;(3)像与物的对应点的连线与镜面垂直;(4)像与物左右位置颠倒;(5)平面镜所成的像是虚像(实像、虚像)。具体总结就是十个字:等大、等距、垂直、反向、虚像。如图所示。 2.虚像是指射入眼睛的光线,其反向延长线的集合点形成的像,如上图所示;虚像能用眼睛直接观看,但不能用光屏接收;实像既可以用光屏承接,也可以用眼睛直接观看。 二、球面镜 1.利用光的反射现象,反射面为平面的叫平面镜,反射面为球面一部分的叫球面镜。 2.利用球面的外表面作反射面的面镜叫做凸面镜;凸面镜对光有发散作用,常用作汽车观后镜来扩大视野。 3.利用球面的内表面作反射面的面镜叫做凹面镜;凹面镜对光有汇聚作用,常用作太阳灶、探照灯等。 1.平面镜成像 平面镜成像是光现象重要知识点,在光现象中占据重要位置。平面镜成像与光的反射密

不可分,两节内容在本章地位相同。本节主要知识点有:平面镜成像规律、面镜的应用。平面镜成像特点在中考中出现的概率很高,因为在考查此问题时,光的反射、平面镜成像特点、成像知识和作图问题都会涉及到,具有代表性。故此类问题应作为重点加以重视。 中考中,有关本节知识点的考题主要集中在平面镜成像规律和平面镜应用上,并经常看到平面镜成像与生活实际相结合,利用平面镜成像特点解释生活中的现象等问题。从常考题型方面来看,对平面镜成像考查的概率很高,并经常以填空题出现;对平面镜应用也属于常考内容,并以选择题出现较多。至于对面镜的考查虽然出现概率不高,但也曾出现过此类考题。纵观历年考试,本节考点出现的考题所占分值一般在1—3分之间。 2.中考题型分析 中考中,出现本节知识点考题的概率较高,大部分都是平面镜成像特点及其应用,并以选择题、填空题出现。 3.考点分类:考点分类见下表 ★考点一:平面镜成像特点 ◆典例一:(中考?广东)关于光现象,下列说法错误的是()。 A.太阳光通过三棱镜会分解成多种色光,这种现象叫光的色散; B.影子是由于光的直线传播形成的; C.物体在平面镜中成正立、放大的实像; D.光从空气射入水中后传播速度会变小

Global warming全球变暖全英文介绍

One of the effects of global warming is the destruction of many important ecosystems.Changing and erratic climate conditions will put our ecosystems to the test, the increase in carbon dioxide will increase the problem. The evidence is clear that global warming and climate change affects physical and biological systems. There will be effects to land, water, and life. Already today, scientists are seeing the effects of global warming on coral reefs, many have been bleached and have died. This is due to warmer ocean waters, and to the fact that some species of plants and animals are simply migrating to better suited geographical regions where water temperatures are more suitable. Melting ice sheets are also making some animals migrate to better regions. This effects the ecosystems in which these plants and animals live. Several climate models have been made and they predict more floods (big floods), drought, wildfires, ocean acidification, and the eventual collapse of many ecosystems throughout the world both on land and at sea. There have been forecasts of things like famine, war, and social unrest, in our days ahead. These are the types of effects global warming could have on our planet. Another important effect that global warming will bring is the loss and endangerment of many species. Did you know that 30 percent of all plant and animal species alive in the world today are at risk of extinction by the year 2050 if average temperatures rise more than 2 to 11.5 degrees Fahrenheit. These mass extinctions will be due to a loss of habitat through desertification, deforestation, and ocean warming. Many plants and animals will also be affected by the inability to adapt to our climate warming.

最新八级上册物理《光现象》平面镜成像_知识点总结教学提纲

1、光的反射类型:镜面反射(光滑表面、反光、刺眼) 、漫反射(粗糙表面、各个方向) 注:1、镜面反射和漫反射均遵循光的反射定律; 2、光反射时,光路可逆,如下图。 2、平面镜成像: (1)、平面镜成像的原理:光的反射定律。平面镜就是平时我们用的镜子。 (2)、观察下图,平面镜成像的特点:等大(大小相同)、等距(离平面镜距离相等)、垂直(垂直于平面镜的底边)、正立(原来的样子)、虚像(不存在的像)。 注:在光学中涉及到的像可分成实像和虚像。它们的共同点是都能被人眼观察到,即都有光线射入人眼。它们的不同点是:实像可以成在光屏上,如小孔成像,照像机成像、幻灯机成像均是实像;而平面镜成像,放大镜成像均是虚像。实像是光线的实际会聚而成,而虚像则是由发散的反射光线或折射光线的反向延长线会聚,形成虚像。观察右图: (1)平面镜成的像和物体等大。 (2)像和物到平面镜的距离相等。 (3)像与物的连线与平面镜垂直。 (4)平面镜成的是正立的虚像。 (3)、平面镜的作用:(1)成像(2)改变光的传播方向(潜望镜) 3、用垂直等距和光路图找物体的像。光路图的画法。 画图中的实线和虚线: (1)实际光线用实线画,加箭头表示光线的行进方向; (2)反向延长线不是实际光线,所以用虚线画,不加箭头; (3)实像用实线画,虚像用虚线画,都要加箭头表示像的正倒; (4)法线等辅助线要用虚线画。 4、球面镜 凹面镜:(1)作用:会聚光线(2)应用:太阳灶、汽车头灯 凸面镜:(1)作用:发散光线(2)应用:汽车后视镜 5、虚像和实像

虚像:非实际光线而是光线的反向沿长线会聚而成的像。 实像:实际光线会聚而成的像叫实像。 在光学中涉及到的像可分成实像和虚像。它们的共同点是都能被人眼观察到,即都有光线射入人眼。它们的不同点是:实像可以成在光屏上,如小孔成像,照像机成像、幻灯机成像均是实像;而平面镜成像,放大镜成像均是虚像。实像是光线的实际会聚而成,而虚像则是由发散的反射光线或折射光线的反向延长线会聚,形成虚像。 6、凸面镜和凹面镜 (1)用球面的外表面作为反射面的叫做凸面镜,用球面的内表面作为反射面的叫做凹面镜。(2)凸面镜对光有发散作用,凹面镜对光有汇聚作用。 (3)凸面镜和凹面镜都遵循光的反射定律。 (4)凸面镜成缩小的像,能扩大视野范围。 汽车中的光学知识 1.汽车驾驶室外面的观后镜是一个凸镜利用凸镜对光线的发散作用和成正立、缩小、虚像的特点,使看到的实物小,观察范围更大,而保证行车安全。 2.汽车头灯里的反射镜是一个凹镜它是利用凹镜能把放在其焦点上的光源发出的光反射成为平行光射出的性质做成的。 3.汽车头灯总要装有横竖条纹的玻璃灯罩。汽车头灯由灯泡、反射镜和灯前玻璃罩组成。根据透镜和棱镜的知识,汽车头灯玻璃罩相当于一个透镜和棱镜的组合体。在夜晚行车时,司机不仅要看清前方路面的情况,还要看清路边行人、路标、岔路口等。透镜和棱镜对光线有折射作用,所以灯罩通过折射,根据实际需要将光分散到需要的方向上,使光均匀柔和地照亮汽车前进的道路和路边的景物,同时这种散光灯罩还能使一部分光微向上折射,以便照明路标和里程碑,从而确保行车安全。 4.轿车上装有茶色玻璃后,行人很难看清车中人的面孔。茶色玻璃能反射一部分光,还会吸收一部分光,这样透进车内的光线较弱。要看清乘客的面孔,必须要从面孔反射足够强的光透射到玻璃外面。由于车内光线较弱,没有足够的光透射出来,所以很难看清乘客的面孔。 5.除大型客车外,绝大多数汽车的前窗都是倾斜的。当汽车的前窗玻璃倾斜时,车内乘客经玻璃反射成的像在车的前上方,而路上的行人是不可能出现在上方的空中的,这样就将车内乘客的像与路上行人分离开来,司机就不会出现错觉。大型客车较大,前窗离地面要比小汽车高得多,即使前窗竖直装,像是与窗同高的,而路上的行人不可能出现在这个高度,所以司机也不会将乘客在窗外的像与路上的行人相混淆。

globalwarming教案

Teaching Plan Contents: Reading Book 6 Unit 4 Global warming I.Analysis of the Teaching Material This article is from a magazine about global warming, which illustrates how global warming has come about and different attitudes to its effects. The passage is long, abstract and far away from their life. What’s more, there are many mouthful professional terms, which increases students’ difficulty while reading, although they have some knowledge about global warming. II. Analysis of the Students Students from Senior Two are the students in an excellent level, who have good abilities to read and speak. This unit talks about global warming, which has been taught in Geography. It will help students understand the text better and I believe the students will be interested in this class. However,because they pay little attention to this topic in the daily life, they may have few desire to speak something about global warming. III. Teaching objectives 1. Knowledge objective 1) Enable the students to analyze how global warming has come about; 2) Get students know different attitudes towards global warming and its effects. 2. Competence objective Improve the students’ reading and speaking abilities. 3. Emotion objective 1) Develop student s’ teamwork. 2) Raise their awareness of global warming. IV. Important points Enable the students to understand how global warming has come about. V. D ifficult points Get the students understand how global warming has come about. Let the students understand the difficult sentences better. ①It is human activity that has caused this global warming rather than a random but natural phenomenon. (Line 6) ②All scientists subscribe to the view that the increase in the earth’s temperature is due t o the burning of fossil fuels like coal, natural gas and oil to produce energy. (Line 18) ③This is when small amounts of gases in the atmosphere, like carbon dioxide, methane and water vapour, trap heat from the sun and therefore warm the earth.(Line 26-29) VI. Teaching aids: Multimedia classroom, printed material VII. Teaching methods: Task-based teaching, communicative teaching method VIII.Teaching procedures: Step 1. Lead in and pre-reading (5 mins ) It’s reported that global temperatures continue to rise, making July 2016 the hottest month in the history of the earth. Did you feel extremely hot in July? When you felt hot, what did you do? Did you feel global temperatures going up quietly? Let’s look at a flash (global temperatures from 1850 to 2016). What information can you get? The earth is becoming warmer and warmer. Is it natural or caused by human being? Do you think what effects global warming will bring about? Is global warming beneficial or harmful? Today we’re going to read a magazine article about global warming. It will work out your puzzles. Please open your book and turn to P26. Today we are going to

平面镜成像___知识点、经典例题、习题

课题平面镜成像 教学目标了解并能描述平面镜成像特点;初步了解凸面镜和凹面镜及其应用; 重点、难点平面镜成像特点 教学内容 一、知识点梳理复习 1、光的反射类型: 镜面反射(光滑表面、反光、刺眼) 、漫反射(粗糙表面、各个方向) 注:1、镜面反射和漫反射均遵循光的反射定律;2、光反射时,光路可逆,如下图。 2、平面镜成像特点 实验名称:探究平面镜成像的特点. 实验目的:探究物与像到镜面的距离, 物、像的大小关系 实验器材:两支大小形状相同的的蜡烛、一块玻璃板、玻璃板支架、一个光屏、一把直尺、一张纸和火柴. 实验步骤:参照如图2-3-1所示的步骤完成实验: (1)将玻璃板垂直架在纸上,在玻璃板前面立一支点燃的蜡烛,透过玻璃板观察其后面的蜡烛的像; (2)将另一未点燃的蜡烛放在玻璃板后,前后左右移动,直到看上去这支蜡烛与前面蜡烛的像重合,此时后面的蜡烛就代替等同于前面蜡烛的像,此时对比物与像的大小关系; (3)用直尺量出此时蜡烛和像到玻璃板的距离,并记录;

(4)改变燃着的蜡烛到玻璃板的距离,连做两次,分别观察蜡烛与像的大小关系,量出蜡烛与像到玻璃板的距离,分别记录下来; (5)将光屏放到像的位置,不透过玻璃板,直接观察光屏上有无像; (6)将玻璃板稍微倾斜一下,不再与桌面垂直,看一看像的变化,还能重合吗? (7)整理实验器材,结束实验. 实验结果:平面镜所成像的大小和物体的大小相等;像到平面镜的距离与物到平面镑的距离相等;平面镜成的是虚像,一句话概括:物与像关于镜面对称(距离相等、大小相等),成虚像. 实验存在的问题分析: (1)用玻璃板代替平面镜 玻璃既能反光又能透光,用玻璃板代替平面镜是为了准确的找到像的位置,便于比较物与像的大小关系及测定物与像到镜面的距离. (2)实验时选用的玻璃板要薄些,如果用厚玻璃做这个实验,玻璃的两个表面都会发生反射,会看到两个不重合的像,不利于实验. (3)两只完全相同的蜡烛 让没有点燃的蜡烛与像重合,这只蜡烛的位置也就是像的位置,这样做的目的是为了便于比较像和物的大小. (4)无论怎样移动物像都无法重合 实验中使玻璃板与白纸垂直,否则,会出现玻璃板后的蜡烛无论怎样移动.都不能与前面蜡烛的像重合的现象(玻璃板倾斜时,像成在玻璃板的斜上方). 平面镜成像特点: (1)平面镜成的像和物体等大。 (2)像和物到平面镜的距离相等。 (3)像与物的连线与平面镜垂直。 (4)平面镜成的是正立的虚像。 (5)、平面镜的作用:(1)成像(2)改变光的传播方向(潜望镜) 5、虚像和实像 虚像:非实际光线而是光线的反向沿长线会聚而成的像。 实像:实际光线会聚而成的像叫实像。 在光学中涉及到的像可分成实像和虚像。它们的共同点是都能被人眼观察到,即都有光线射入人眼。它们的不同点是:实像可以成在光屏上,如小孔成像,照像机成像、幻灯机成像均是实像;而平面镜成像,放大镜成像均是虚像。实像是光线的实际会聚而成, 而虚像则是由发散的反射光线或折射光线的反向延长线会聚,形成虚像。 3、用垂直等距和光路图找物体的像。光路图的画法。

平面镜成像知识点的例题及其解析

平面镜成像知识点的例题及其解析 【例题1】请利用平面镜成像的特点在图中作出AB物体在平面镜中的像,保留作图痕迹。 答案如图所示: 解析:先作出端点A、B关于平面镜的对称点A′、B′,用虚线连接A′、B′即为物体AB 的像,如图所示。 【例题2】如图是验证“平面镜成像特点”的实验装置,其中A为玻璃板前点燃的蜡烛,B 为玻璃板后未点燃的蜡烛。有关本实验的说法错误的是() A.玻璃板应该与桌面垂直 B.实验宜在较暗的环境中进行 C.眼睛应从B一侧观察成像情况 D.蜡烛燃烧较长时间后像物不再重合 答案:C 解析:解答此题从以下知识点入手: ①实验中玻璃板如果不垂直于桌面,后面的蜡烛无法与前面蜡烛的像完全重合; ②眼睛在A的一侧观察。 ③物体射出的光线对人眼刺激越强,人眼感觉物体越亮,物体经过平面镜反射,反射光线进入人眼的光线越多,人眼感到物体的像越亮。在比较亮的环境中,很多物体射出光都对眼睛有刺激,干扰人的视线; ④平面镜成像特点之一:物像等大。 A.实验时玻璃板如果不竖直,不论怎样移动后面的蜡烛都不可能与前面蜡烛的像完全重合,就无法验证像的位置和大小,所以玻璃板应与水平桌面垂直放置。故A正确; B.在比较明亮的环境中,很多物体都在射出光线,干扰人的视线,在较黑暗的环境中,蜡烛是最亮的,蜡烛射向平面镜的光线最多,反射光线最多,进入人眼的光线最多,感觉蜡烛的像最亮。所以在比较黑暗的环境中进行实验,故B正确; C.寻找蜡烛A的像的位置时,眼睛应在蜡烛A一侧观察,在蜡烛B的一侧不能看到蜡烛A 的像;故C错误;

D.平面镜所成的像,物像等大,蜡烛燃烧较长时间后像物不再重合,故D正确。 【例题3】小明身高1.6m,站在距平面镜3m处,能够看到自己的全身像。则他的像高m,像到平面镜的距离为m。 答案:1.6;3 解析:根据平面镜成像的特点:①所成的像是虚像;②像和物体形状、大小相同; ③像和物体各对应点的连线与平面镜垂直;④像和物体到平面镜间距离相等来解答此题。(1)根据平面镜成像的特点,像和物体形状大小相同,所以身高1.6m的小明同学她在镜中的像高仍然为1.6m; (2)由平面镜成像的特点知,像和物体到平面镜间距离相等,当人到镜面的距离3m时,像到镜面的距离也为3m。 【例题4】如图,A、B两地相距4km,MN是与AB连线平行的一条小河的河岸,AB到河岸的垂直距离为3km,小军要从A处走到河岸取水然后送到B处,他先沿着垂直于河岸的方向到D点取水,再沿直线DB到B处。若小军的速度大小恒为5km/h,不考虑取水停留的时间。 (1)求小军完成这次取水和送水任务所需的时间。 (2)为了找到一条最短的路线(即从A到河岸和从河岸到B的总路程最短),可以将MN看成一个平面镜,从A点作出一条光线经MN反射后恰能通过B点,请你证明入射点O即为最短路线的取水点。 答案:(1)总路程 s=AD+DB=(3+5)km=8km 总时间 t=s/t=8/5h=1.6h (2)如图,根据平面镜成像的特点,作出A点关于MN所成的虚像A′连接A′D和A′O,AO=A′O,且A′、O、B在一条直线上,故取水点为O时的路线长度s=AO+OB=A′O+OB= A′B,在O点以外的河岸上任取一点P,路线的长度s′=AP+PB= A′P+PB 由三角形知识得A′B<A′P+PB,即s<s′ 故入射点O为最短路线的取水点。

2017_2018学年高中英语大题精做04Globalwarming含解析新人教版

Unit 4 Global warming I. 完形填空 阅读下面短文,掌握其大意,然后从各小题所给的四个选项 (A、B、C和D) 中,选出 最佳选项。 Today the scientific community is in almost total agreement that the earth’s climate is changing and that this represents a huge threat to the planet and to us. According to a survey, with only 69% accepting the earth is warming— only 1/4 Americans see global warming as a major threat, public opinion 1 the scientific conclusion. Climate scientists and campaigners have long debated how to better communicate the message to nonexperts so that climate science can be 2 into action. According to Christopher Rapley, the usual tactic(策略) of climate experts to provide the public wit h information isn’t 3 because "it does not address key potential causes." We are all exposed to the evidence of climate change on an almost a daily basis. The information is almost 4 . Then what’s wrong? 5 our brains. Daniel Gilbert mentioned our brains’ failure to accu rately notice gradual change. Robert Gifford also __6__ the point about our brains’ difficulty in grasping climate change because of limited cognition and social __7__ with other people ("Why should we change if X won’t?") ." A more powerful barrier is the 8 of perceived(感知的) be havioral control; ‘I’ m only one person; what can I do ?’ is certainly a big one." For many, the first challenge will be in recognizing barriers 9 they can overcome them. But for those of us who understand that climate change is a problem yet make little effort to cut the number of overseas trips we make or the amount of meat we consume, neither the uncaring attitude nor denial really explains the 10 between our actions and beliefs. Lertzman has come to the conclusion that the conflict between __11 _ both the planet and our way of life is too painful to bear. "When we don’t 12 the pain of that, that’s when we get 13 and

高中英语《UnitGlobalwarming》阅读训练人教版选修

Global Warming Section A 本文词数:302 参考时间:2'40'' Rising temperatures in coming years would lead to less sea ice in the Southern Ocean that surrounds Antarctica and fewer habitats and feeding grounds for penguins, says the World Wildlife Fund (世界自然基金会) in its report 2 Degrees is Too Much. Antarctica and the Arctic are the most threatened regions from climate change. In the Antarctica, the temperature has risen 2.5 degrees in the past 50 years. This speed is nearly five times faster than that before the Industrial Revolution. It is mainly caused by burning fossil fuels. Unless nations reduce carbon dioxide emission1, the world will warm by an average of 2 degrees in less than 40 years. Rich nations should agree to reduce greenhouse gas emission. Temperatures near the Poles have risen much faster, which has led glaciers2 on the Antarctic Peninsula to melt3 quickly. The situation is quite critical, because in the past 50 years the number of emperor penguins (帝企鹅) has decreased by 50 percent across the whole Antarctica. On the Antarctic Peninsula’s northwest coast, the number of Adelie penguins (阿德里企鹅) has dropped surprisingly over the past 25 years. Fifty percent of the habitats of the emperor penguin and 75 percent of the habitats of the Adelie penguin face a rapid reduction, or even disappearance, if the global temperature rises 2 degrees above pre-industrial levels. With a 2-degree increase in global temperature and the decrease in sea ice thickness, emperor penguins will find it difficult to find new areas to live. With less sea ice, penguins could be pushed further south, but this could prevent them from hunting for food during the dark winters, because they need at least a few hours of daylight to find their food. Notes: 1. emission n. 排放 2. glacier n. 冰川 3. melt v. 融化 词数:150处理时间:2′45″ Read the passage and then choose the best answer for each question. 1. The purpose of the passage is to _____. A. introduce readers to the Adelie penguins and emperor penguins B. tell readers about the rising temperatures in the Antarctica C. tell readers about the effect of global warming D. warn people that Antarctica is becoming smaller and smaller 2. In the writer’s opinion, what has caused global warming? A. That the earth is getting hotter and hotter. B. That the atmosphere of the earth is becoming thinner. C. That carbon dioxide emission is too high. D. That the use of oxygen in the air is out of control. 3. From the first paragraph, what do you think the author wants to tell us?

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