问题 问答题

如图甲是用水来冷却热牛奶时拍摄的照片情景(牛奶与水的密度相差很小).图乙是记录牛奶、水的温度随时间变化的图象,图中表示热奶温度随时间变化的曲线应是______(填写I或Ⅱ);图中A点的物理意义是______.有同学想根据图象分析比较“牛奶和水的比热容谁大”,请问他______(“能”或“不能”)达到目的,请简单说明,理由是______.

答案

热牛奶放入水中,牛奶的温度降低,水的温度升高,直到二者温度相等时,即18℃温度不再变化.热奶温度随时间变化的曲线应是Ⅰ.

A点表示的是奶和水最后共同的温度.

若要比较水和牛奶的比热容大小,必须使奶和水的质量相同,并且同样受热、放热,然后比较温度的变化情况.在此题中奶的质量小于水的质量,所以不能达到目的.

故答案为:I;热牛奶与水最后的共同温度为18℃;不能;牛奶的质量比水少,但变化的温度比水大.

阅读理解

Life in the twenty-first century

The World Future Society is a group of people from more than 80 countries who are interested in how modern technology is making our world better, and who write reports about how it will change our lives.                                                                                                                                            The things that we will be able to do in the twenty-first century (since the year 2000) should help us live better lives in many ways, at home and at work, in our own country and around the world. Here are just some of them, put into five groups.

People

People may live for up to 120 years and use new technology to help when people go blind, deaf and have other problems. The number of people over a hundred years old could go from 135,000 today to 2.2 million people by 2050. By 2015 people think that 100 million workers will be able to work from home for a company in a different country by using the Internet.

Money

Worldwide e-business will become even more successful with online shops that sell special products for each person, which will be brought to their house the next day.

Environment

The technology for making energy from wind and the Sun is growing very quickly. In the future wind and Sun energy could become much cheaper and many more countries could use it. This would be very useful in poor countries. The air in big cities would also become much cleaner and healthier as a result.

Society and culture

The Internet will help to create more worldwide friendships. Families may spend more time together as people will be able to do 24-hour online banking and shopping.

Technology      

The new science of “nanotechnology” (very small robots or machines) will make all sorts of products smaller and lighter. Very, very small machines could take away rubbish, make things in factories, and help inside the human body by taking away fat. By 2012 people will be able to wear these small machines that look like watches, which will give them lots of information about their body and keep them healthy.

小题1:What does the World Future Society do?

A.Look at how technology will make people happy.

B.Look at how technology will change the world.

C.Make technology work better for themselves.

D.Make small machines to make us healthier.小题2: How will technology help people?

A.Help all people live for over 120 years.

B.Help disabled people to get jobs.

C.Make people healthier and live longer.

D.Help workers to use the Internet.小题3:How will people go shopping?

A.In special shops.

B.Using the Internet at certain times.

C.Using the Internet any time of the day.

D.Using nanotechnology.小题4: How will technology help the environment?

A.Poor countries will have enough energy.

B.Wind energy will be cheaper than Sun energy.

C.We will not need wind and Sun energy.

D.Wind and Sun energy will be cheaper.小题5:The new science of “nanotechnology” will _______.

A.drive small machines to work for people

B.make good-quality watches

C.allow people to eat more

D.make very small products

单项选择题