问题 填空题

水的比热容为4.2×103焦/(千克-℃),其物理意义是______.有一杯质量为200克、温度为20℃的水,加热后使其温度升高到40℃,这杯水的比热容将______.(选填“变大”、“变小”或“不变”).

答案

(1)水的比热容为4.2×103J/(kg?℃).它表示:1kg的水温度升高(或降低)1℃所吸收(或放出)的热量是4.2×103J;

(2)比热容是物质的一种特性,与物质的温度无关,即加热后水的比热容不变.

故答案为:1kg的水温度升高(或降低)1℃所吸收(或放出)的热量是4.2×103J;不变.

选择题
单项选择题

Research on animal intelligence always makes us wonder just how smart humans are. (1) the fruit-fly experiments described by Carl Zimmer in the Science Times. Fruit flies who were taught to be smarter than the average fruit fly (2) to live shorter lives. This suggests that (3) bulbs burn longer, that there is a(n) (4) in not being too bright.

Intelligence, it (5) , is a high-priced option. It takes more upkeep, burns more fuel and is slow (6) the starting line because it depends on learning — a(n) (7) process — instead of instinct. Plenty of other species are able to learn, and one of the things they’ve apparently learned is when to (8) .

Is there an adaptive value to (9) intelligence That’s the question behind this new research. Instead of casting a wistful glance (10) at all the species we’ve left in the dust I.Q.-wise, it implicitly asks what the real (11) of our own intelligence might be. This is (12) the mind of every animal we’ve ever met.

Research on animal intelligence also makes us wonder what experiments animals would (13) on humans if they had the chance. Every cat with an owner, (14) , is running a small-scale study in operant conditioning. We believe that (15) animals ran the labs, they would test us to (16) the limits of our patience, our faithfulness, our memory for locations. They would try to decide what intelligence in humans is really (17) , not merely how much of it there is. (18) , they would hope to study a(n) (19) question: Are humans actually aware of the world they live in (20) the results are inconclusive.

10()

A.upward

B.forward

C.afterward

D.backward