题干

如图所示的实验装置,研究体积不变时的气体压强与温度的关系,当时大气压为H(cm)汞柱.封有一定质量气体的烧瓶,浸在冰水混合物中,U形压强计可动管A和固定管B中的水银面刚好相平.将烧瓶浸入温度为t℃的热水中时B管的水银面将____,这时应将A管____,(以上两空填“上升”或“下降”)使B管中水银面____.记下此时A、B两管中水银面的高度差为h(cm),此状态下瓶中气体的压强为____

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答案(点此获取答案解析)

下降,上升,回到原来位置,(H+h)cmHg

同类题5

请阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

E

    The traditional distinction between products that satisfy needs and those satisfy wants is no longer  adequate to describe classes of products. In today's prosperous societies, the distinction has become unclear because so many wants have been turned into needs. A writer, for instance,can work with paper and pencils. These are legal needs for the task. But the work can be done more quickly and efficiently with a word processor. Thus a computer is soon viewed as a need rather than a want.

   In the field of marketing, consumer goods are classed according to the way in which they are purchased. The two main classes are convenience goods and shopping goods. Two lesser types are specialty goods and unsought(主动提供的)goods. It must be emphasized that all of these types are based on the way shoppers think about products. not on the nature of the products themselves. What is regarded as a convenience item in France (wine, for example) should be a specialty goods in the United States.

    People do not spend a great deal of time shopping for such convenience items as groceries, newspapers, toothpaste, aspirin, and candy. The buying of convenience goods may be done routinely, as some families buy groceries once a week. Such regularly purchased items are called staples. Sometimes convenience products are bought without enough thinking; someone has a sudden desire for an ice cream sundae on a hot day. Or they may be purchased as emergency items.

    Shopping goods are items for which customers search. They compare prices. quality, and styles, and may visit a number of stores before making a decision. Buying an automobile is often done this way.

    Shopping goods fail into two classes: those that are recognized as basically the same and those that are regarded as different. Items that are looked upon as basically the same include such things as home appliances, television sets, and automobiles. Having decided on the model desired, the customer is primarily interested in getting the item at the most favorable price. Items regarded as essentially different include clothing, furniture, and dishes. Quality, style and fashion will either take precedence(优先)over price, or they win not matter at all.