2002年诺贝尔物理学奖中的一项,是奖励美国科学家贾科尼和日本科学家小柴晶俊发现

题型:选择题

问题:

2002年诺贝尔物理学奖中的一项,是奖励美国科学家贾科尼和日本科学家小柴晶俊发现了宇宙X射线源.X射线是一种高频电磁波,若X射线在真空中的波长为λ,以h表示普朗克常量,c表示真空的光速,以E和m分别表示X射线每个光子的能量和质量,则(  )

A.E=,m=0

B.E=,m=

C.E=,m=0

D.E=,m=

考点:X射线α、β、γ射线
题型:选择题

阅读理解。

      John is six years old. He can read and write well. But he can't tell the time. His mother,  Mrs. Brown

teaches him many times, but he still can't tell. He would say "breakfast time", “lunchtime" and "teatime"

instead of (代替) saying eight o'clock, twelve o'clock and four o'clock in the afternoon. His mother doesn't know how to help him.

     One day John's aunt, Mary, comes to see his mother. His mother tells her about that. His aunt says, "

Let me help you. I think I can help him. "

     When John comes home after school, Mary begins (开始 ) to  teach  him.

     "Can you count, John ?" she asks him.

     "Yes. One  ,  two,  three,  four. . . "John says.

     " That's fine. Now I put the long hand (钟表的长指针) on twelve and the short hand on one-hat is

one o'clock. If I put the short hand on two, what is the time?"

     "Two o'clock, "

     "Good. And on three?"

     "Three o'clock. "

     Then it is four o'clock in the afternoon, and John's aunt asks him, "What time is it now.

John?" "Teatime, Aunt, and I am very hungry. John looks at the clock and answers.

1. John 's mother can't teach him how to_______

A. read

B. write

C. tell the time

D. count

2.when it's twelve o'clock John says it's _______

A. breakfast time

B. lunch time

C. teatime

D. dinner time

3. The word "count" may mean "_______"

A.计算

B.说出

C.认为

D.数数

4. The long hand is on twelve, and the shorthand is on five. What's the time?

A. It's twelve.

B. It's five.

C. It's four.

D. It's five twelve.

5. From the passage, we know_______

A. John says teatime instead of four o'clock in the afternoon.

B. John has a nice watch.

C. There is something wrong with John's watch.

D. John isn't very clever.

题型:选择题

探究“平面镜成像的特点”时,常选用一块玻璃作为平面镜,将玻璃板竖直架在一把直尺的上面,再取两段相同的蜡烛.将一只点燃的蜡烛放在镜前,另选一只相同的未点燃的蜡烛放在镜后进行观察.

(1)用玻璃板代替平面镜,主要是利用玻璃板透明的特点,便于 ______;

(2) 如果玻璃板没有放正,将对实验产生什么影响?

答:______.

(3)直尺的作用是便于比较像与物 ______的关系;

(4)两段相同的蜡烛是为了比较物与像 ______的关系;

(5)移去后面的蜡烛B,并在其所在位置上放一光屏,则光屏上 ______接收到蜡烛烛焰的像(选填“能”或“不能”).

(6)对着玻璃板既可看到前面蜡烛在玻璃板后所成的像,同时又可看到在玻璃板后的蜡烛. 前者是光的 ______形成的像,后者是光的 ______形成的像.

题型:选择题

2010年为国际生物多样性年,下列对保护生物多样性关系不大的是

A.将濒危物种迁出原地

B.将动物领养回家

C.建立自然保护区

D.建立种子基因库

题型:选择题

俄国封建势力不再占统治地位是在

A.1861年改革后

B.列宁诞生时

C.1917年二月革命时

D.1917年十月革命时

题型:选择题

对法与国家的关系有如下几种表达,其中哪项是不正确的( )

A.法律形式直接受国家形式的影响

B.国家的存在以法的存在为前提条件

C.法律规定国家的性质及组成,国家的性质决定法律的性质

D.国家机构必须依靠法律组织、建立和发展

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