问题 填空题

“世界物理年”决议的作出是与爱因斯坦的相对论时空观有关.一个时钟,在它与观察者有不同相对速度的情况下,时钟的频率是不同的,它们之间的关系如图所示.由此可知,当时钟和观察者的相对速度达到0.6c(c为真空中的光速)时,时钟的周期大约为______.在日常生活中,我们无法察觉时钟周期的变化的现象,是因为观察者相对于时钟的运动速度______.若在高速运行的飞船上有一只表,从地面上观察,飞船上的一切物理、化学过程和生命过程都变______(填“快”或“慢”)了.

答案

根据图中数据可知,当时钟和观察者的相对速度达到0.6c时,对应时钟的频率为0.4Hz,则周期为2.5s.

日常生活中,我们无法察觉是因为运动速度远小于速度c.

根据钟慢效应得在高速运行状态,时钟变慢.

故答案为:2.5s 远小于光速c 慢.

选择题
阅读理解

阅读理解。

     About ten men in every hundred suffer from color blindness in some way. Women are luckier; only about

one in two hundred is affected in this matter, Perhaps, after all, it is safer to be driven by a woman!

     There are different forms of color blindness. In some cases a man may not be able to see deep red. He

may think that red, orange and yellow are all shadows of green. Sometimes a person cannot tell the difference

between blue and green. In rare cases an unlucky man may see everything in shades of green-a strange world

indeed.

     Color blindness in human beings is a strange thing to explain. In a single eye there are millions of very small

things called "cones" (圆锥细胞). These help us to see in a bright light and to tell the difference between colors.

There are also millions of "rods" (棒条体), but these are used for seeing when it is near dark. They show us

shape but no color.

     Some insects have favorite colors. Mosquitoes (蚊子) prefer blue to yellow. A red light will not attract

insects, but a blue lamp will. In a similar way human beings also have favorite colors. Yet we are lucky. With

the aid of the cones in our eyes we tan see many beautiful colors by day, and with the aid of the rods we can

see shapes at night. One day we may even learn more about the invisible (看不见的) colors around us.

1. The passage is mainly about _____.

A. color and its surprising effects

B. women being luckier than men

C. danger caused by color blindness

D. color blindness 

2. According to the passage, with the help of the "cones",we can _____.

A. tell different shapes

B. see in a weak light

C. kill mosquitoes

D. tell orange from yellow

3. Why do some people 8ay it is safer to be driven by women?

A. Women are more careful.

B. There are fewer color-blind women.

C. Women are fonder of driving than men.

D. Women are weaker but quicker in thinking.

4. Which of the statements about the color-blind is true?

A. Not all of them have the same problem in recognizing color.

B. None of them can see deep red.

C. None of them can tell the difference between blue and green.

D. All of them see everything in shades of green.

5. We can attract and kill mosquitoes by using a _____.

A. red light

B. yellow light

C. blue light

D. green light