问题 选择题

1827年,英国植物学家布朗发现了悬浮在水中的花粉微粒的运动.图所示的是显微镜下观察到的三颗花粉微粒做布朗运动的情况.从实验中可以获取的正确信息是(  )

A.实验中可以观察到微粒越大,布朗运动越明显

B.实验中可以观察到温度越高,布朗运动越明显

C.布朗运动说明了花粉分子的无规则运动

D.布朗运动说明了水分子的无规则运动

答案

BD

考点:

专题:热学、光学和原子物理学.

分析:如图所示的是显微镜下观察到的三颗花粉微粒做布朗运动的情况,其运动不是自身运动,而是花粉微粒周围的分子做无规则运动,对其撞击产生的运动.

解答:解:A、由于花粉微粒是受其周围分子无规则运动的撞击,而产生的运动,所以当微粒越大时,来自各方向的撞击抵消的越多,因此布朗运动越不明显,故A不正确;

B、实验中当温度超高时,分子无规则运动越剧烈,分子撞击微粒越频繁,导致微粒运动越明显.故B正确

C、布朗运动其实是微粒的运动,而微粒的运动是由分子运动撞击产生的.故C不正确;

D、布朗运动其实是微粒的运动,而微粒的运动是由分子运动撞击产生的,说明水分子的无规则运动.故D正确

故选:BD.

点评:考查了微粒的运动与分子的运动的区别,同时涉及温度越高,运动越剧烈.

单项选择题 共用题干题
单项选择题

In 1993, New York State ordered stores to charge a deposit on beverage (饮料) containers. Within a year, consumers had returned millions of aluminum cans and glass and plastic bottles. Plenty of companies were eager to accept the aluminum and glass as raw materials for new products, but because few could figure out what to do with the plastic, much of it wound up buried in landfills (垃圾填埋场). The problem was not limited to New York. Unfortunately, there were too few uses for second-hand plastic.

Today, one out of five plastic soda bottles is recycled (回收利用) in the United States. The reason for the change is that now there are dozens of companies across the country buying discarded plastic soda bottles and turning them into fence posts, paint brushes, etc.

As the New York experience shows, recycling involves more than simply separating valuable materials from the rest of the rubbish. A discard remains a discard until somebody figures out how to give it a second life—and until economic arrangements exist to give that second life value. Without adequate markets to absorb materials collected for recycling, throwaways actually depress prices for used materials.

Shrinking landfill space, and rising costs for burying and burning rubbish are forcing local governments to look more closely at recycling. In many areas, the East Coast especially, recycling is already the least expensive waste-management option. For every ton of waste recycled, a city avoids paying for its disposal, which, in parts of New York, amounts to savings of more than $100 per ton. Recycling also stimulates the local economy by creating jobs and trims the pollution control and energy costs of industries that make recycled products by giving them a more refined raw material.

Recycling has become the first choice for the disposal of rubbish because ().

A. local governments find it easy to manage

B. recycling has great appeal for the jobless

C. recycling causes little pollution

D. other methods are more expensive