题目内容
水的比热容是煤油比热容的两倍,若水和煤油的质量之比为1:2,吸收的热量之比为2:3,则水和煤油升高的温度之比为( )A.2:3
B.3:2
C.4:3
D.3:4
【答案】分析:已知水和煤油的比热容关系、质量之比和吸收的热量的之比,可利用公式△t=
计算物体温度变化之比.
解答:解:
由题知,水的比热容是煤油比热容的两倍,即:
=
,而
=
、吸收的热量之比:
=
,
∵Q=cm△t,
∴△t=
,
∴它们升高的温度之比为:
=
:
=
×
×
=
×
×
=
.
故选A.
点评:本题考查学生对热量公式的掌握和运用,并可以利用其公式变形计算物体温度变化之比,在代入数值的时候应注意要一一对应,这是一个比较容易出错的地方.
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/0.png)
解答:解:
由题知,水的比热容是煤油比热容的两倍,即:
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/1.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/2.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/3.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/4.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/5.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/6.png)
∵Q=cm△t,
∴△t=
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/7.png)
∴它们升高的温度之比为:
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/8.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/9.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/10.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/11.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/12.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/13.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/14.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/15.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/16.png)
![](http://thumb.1010pic.com/pic6/res/czwl/web/STSource/20131024153745683485110/SYS201310241537456834851015_DA/17.png)
故选A.
点评:本题考查学生对热量公式的掌握和运用,并可以利用其公式变形计算物体温度变化之比,在代入数值的时候应注意要一一对应,这是一个比较容易出错的地方.
![](http://thumb2018.1010pic.com/images/loading.gif)
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