小明根据下表所提供的几种物质的比热容得出以下结论，其中正确的_爱下问搜题

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问题多选题

小明根据下表所提供的几种物质的比热容得出以下结论，其中正确的是

A．固体的比热容一定比液体的比热容小

B．同种物质的比热容随物态变化而发生改变

C．质量为1 kg的煤油放出2.1×10³J的热量，温度升高1℃

D．质量相等的水和酒精，吸收相同热量后，酒精的温度变化大

答案

BD

题目分析：冰是固体，但其比热容大于水银的比热容，A错；冰和水是同种物质，但比热容不同，B对；质量为1 kg的煤油放出2.1×10³J的热量，温度降低1℃，C错；酒精的比热容小于水的比热容，根据，质量相等的水和酒精，吸收相同的热量后，酒精升温较多，D对。

阅读理解

Steve Jobs was one of the fathers of the personal computer times and the founder of Apple. He was also one of the giants of the information age. Here are some of his greatest contributions.

AppleⅡ
Jobs and Steve Wozniak founded Apple Computers inc.in 1976. A year later, the AppleⅡwas invented. This production was the world’s first mass-market personal computer.

The iMac
Under Job’s leadership, Apple introduced the all-in-one iMac computer in 1988. The iMac became the first machine which offered only a CD-ROM slot (插槽).

The iPad
By 2010, Steve Jobs was confident that the world was ready to have a tablet computer that would be great for watching movies and playing games. The touch-sen-sitive iPad was a great success.

The iPhone 4s
The iPhone 4s came out on October 4, 2011, in America. It looks like the iPhone 4. It has a larger and wider screen and a slimmer yet wider case. It has a better camera and faster data transfer (数据传输) speeds.

小题1:When was the AppleⅡinvented?

小题2:Which of the following was the iMac which came out in 1988 different from others?

A．People could play games on it.

B．It offered only one CD-ROM slot.

C．It had one camera in it.

D．It had a larger screen.

小题3:What was the latest product?

A．The iPhone 4s.

B．The AppleⅡ.

小题4:From the passage, we can know that the iPad .

A．has a better camera

B．is the first personal computer

C．has a CD-ROM slot

D．is great for watching movies

小题5:According to the passage, which of the following about the iPhone 4s is TRUE?

A．Its screen is the same size as the iPhone 4.

B．It has a smaller screen and slimmer case than the iPhone 4.

C．It has a larger screen and a better camera than the iPhone 4.

D．It uses more time to transfer the same date than the iPhone 4.

计算题

如图所示，沿水平方向放置一条平直光滑槽，它垂直穿过开有小孔的两平行薄板，板相距3.5L。槽内有两个质量均为m的小球A和B，球A带电量为+2q，球B带电量为－3q，两球由长为2L的轻杆相连，组成一带电系统。最初A和B分别静止于左板的两侧，离板的距离均为L。若视小球为质点，不计轻杆的质量，在两板间加上与槽平行向右的匀强电场E后（设槽和轻杆由特殊绝缘材料制成，不影响电场的分布），求：

（1）球B刚进入电场时，带电系统的速度大小；

（2）带电系统从开始运动到速度第一次为零所需的时间及球A相对右板的位置。