问题 问答题

小亮同学用一个未知焦距的凸透镜探究凸透镜成像规律:

(1)将蜡烛、凸透镜和光屏放在光具座上,并使烛焰、透镜和光屏三者的中心在一条与光具座平行的直线上,调整的目的是______.小亮同学按要求进行观察和测量,并将观测情况记录在下表中:

实验序号物距/cm像距/cm像的性质
1206.7倒立、缩小的实像
2157.5
31010倒立、等大的实像
47.5倒立、放大的实像
54--正立、放大的虚像
(2)此凸透镜的焦距为______cm.

(3)在表中填出实验序号2中像的性质,实验序号4中像距的大小.

(4)当蜡烛从远处向透镜靠近时,仍要在光屏上得到清晰的像,光屏应向______(选填“靠近”或“远离”)透镜的方向移动.

答案

(1)为使烛焰的像能成在光屏的中央,实验前需调节烛焰、凸透镜、光屏,使它们的中心大致在同一高度处.

故答案为:使像能完整的成在光屏的中央.

(2)由表格中数据知,当物距等于10cm时,成倒立、等大的实像,像距也为10cm,所以10cm=2f,则f=5cm.

故答案为:5.

(3)在序号2中,物距为15cm,u>2f,所以成倒立、缩小的实像.

由序号2知,当u=15cm时,v=7.5cm,根据光路的可逆性,所以当u=7.5cm时,像距v=15cm.

故答案为:倒立、缩小的实像;15.

(4)成实像时,物距减小,像距增大,成的像也增大.

所以远离当蜡烛从远处向透镜靠近时,仍要在光屏上得到清晰的像,光屏应远离透镜.

故答案为:远离.

完形填空

第二节:完形填空(共20小题;每小题1分,满分20分)

请认真阅读下面短文,从短文后个题所给的A、B、C、D四个选项中,选出最佳选项,并在答题卡上将该项涂黑。

Another person’s enthusiasm was what set me moving toward the success I have achieved.That person was my stepmother.

I was nine years old when she enterd our home in rural Virginia. My father__36__me to her with these words:“I would like you to meet the fellow who is___37  for being the worst boy in this county and will probably start throwing rocks at you no ___38  than tomorrow morning.”

My stepmother walked over to me, ___39  my head slightly upward,and looked me right in the eye.Then she looked at my father and replied,“You are ___40  .This is not the worst boy at all, ___41   the smartest one who hasn’t yet found an outlet(释放的途径)for his enthusiasm.”

That statement began a(n) ___42   between us.No one had ever called me smart,My family and neighbors had built me up in my ___43   as a bad boy . My stepmother changed all that.

She changed many things.She ___44   my father to go to a dental school,from which he graduated with honors.She moved our family into the county srat,where my father’s career could be more ___45   and my brother and I could be better___46   .

When I turned fourteen,she bought me a secondhand___47   and told me that she believed that I could become a writer.I knew her ernthusiasm,I___48

it had alreadly improved our lives.I accepted her ___49  and began to write for local newspapers.I was doing the same kind of___50   that great day I went to interview Andrew Carnegie and received the task which became my life’s work later.I wasn’t the ___51   beneficiary (受益者).My father became the ___52   man in town.My brother and stepbrthers became a physician,a dentist,a lawyer,and a college president.

What power __53  has!When that power is released to support the certainty of one’s purpose and is ___54  strengthened by faith,it becomes an irresistible(不可抗拒的)force which poverty and temporary defeat can never ___55   .

You can communicate that power to anyone who needs it.This is probably the greatest work you can do with your enthusiasm.

36.A.rushed          B.sent          C.carried       D.introduced

37.A.distinguished      B.favored       C.mistaken      D.rewarded

38. A.sooner          B.later         C.longer        D.earlier

39. A.dragged         B.shook        C.raised        D.bent

40. A.perfect          B.right         C.wrong        D.impolite

41. A.but             B.so           C.and          D.or

42. A.ageement        B.friendship     C.gap           D.relationship

43. A.opinion         B.image        C.espectation      D.mind

44. A.begged          B.persuaded     C.ordered        D.invited

45. A.successful       B.meaningful     C.helpful        D.useful

46. A.treared         B.entertained     C.educated       D.respected

47. A.cemera         B.radio         C.bicycle        D.typewriter

48. A.considered      B.suspected      C.ignored       D.appreciated

49. A.belief          B.request        C.criticism       D.description

50. A.teahing         B.writing        C.studying      D.reading

51. A.next           B.same          C.only         D.real

52. A.cleverest       B.wealthiest      C.strongest      D.bealthiest

53. A.ebthusiasm      B.sympathy       C.fortune       D.confidence

54. A.deliberately      B.happily        C.traditionally     D.constantly

55. A.win           B.match          C.reach         D.doubt

判断题