小明家新安装了一台容积为0.5m3的太阳能热水器，加满水后，经过4h阳光的照射，水温由原来的20℃升高到了40℃．问：在这4h内水吸收了多少热量？若这些热量由效率为20%的火炉燃烧焦炭来提供，则需要燃

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小明家新安装了一台容积为0.5m³的太阳能热水器，加满水后，经过4h阳光的照射，水温由原来的20℃升高到了40℃．问：在这4h内水吸收了多少热量？若这些热量由效率为20%的火炉燃烧焦炭来提供，则需要燃烧多少千克焦炭？[水的比热容c_水=4.2×10³J/（kg•℃）、焦炭的热值q=3.0×10⁷J/kg]．

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解：（1）由ρ=

得水的质量为：

m=ρV=1×10³kg/m³×0.5m³=500kg；

则水吸收的热量为：

Q_吸=c_水

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阅读下列短文，从下面每小题的A、B、C、D四个选项中选出最佳选项。

Lee Ming, Ivy, Tony and Terrence are from four different countries. The followings are their diet menus for one day:

	breakfast	lunch	dinner
Lee Ming from China	He eats porridge ( 麦片粥 ). He doesn't like roast bread but he likes Chinese steamed bread. He likes drinking soybean milk.	He eats rice, chicken, pork and vegetables for lunch.	He eats the same food as lunch for dinner. After dinner, he will eat some fruit.
Ivy from the USA	She likes drinking orange juice or coffee. She eats oatmeal (燕麦片) and roast bread for breakfast.	Her house is far away from her company. So she often has sandwiches, vegetables and soft drinks for lunch.	After work, she shares a big dinner with her family. They will taste steak, beef and seafood. She will enjoy some dessert and some fruit after dinner.
Tony From Britain	He eats grain with milk and bread for his breakfast. He drinks a cup of orange juice every day.	He doesn't have much time for lunch. So he often has fast food such as chips, hamburgers, hot dogs and soft drinks.	He eats beef and chips for dinner. He likes ice cream after dinner.
Terrence from France	He eats grain products, bread and drinks coffee.	He likes spaghetti (意大利面条), meat, fish and vegetables for lunch. He drinks some wine during lunch. He has some fruit after lunch.	He eats soup, ham, cheese, and spaghetti. He drinks some wine as well.

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