问题 计算题

小明同学为测量地球表面植物吸收太阳能的本领,做了如下实验:用一脸盆装6kg的水,水面的表面积为0.1m2,经太阳垂直照射15min,温度升高了5℃.请计算:

(1)实验时6kg的水吸收了多少热量?

(2)若地表植物接收太阳能的能力与水相等,每m2绿色植物每秒接收的太阳能为多少J?

答案

解:

(1)Q=cm△t=4.2×103J/(kg·℃)×6kg×5℃=1.26×105J;

(2)每m2水面1s吸收的太阳能:Q'==1400J,

单项选择题
单项选择题

Few people would defend the Victorian attitude to children, but if you were a parent in those days, at least you knew where you stood: children were to be seen and not heard. Freud and his company did away with all that and parents have been bewildered ever since. The child’s happiness is all-important, the psychologists say, but what about the parents’ happiness Parents suffer continually from fear and guilt while their children gaily romp about pulling the place apart. A good "old-fashioned" spanking is out of the question: no modern child-rearing manual would permit such barbarity. The trouble is you are not allowed even to shout. Who knows what deep psychological wounds you might inflict The poor child may never recover from the dreadful traumatic experience. So it is that parents bend over backwards to avoid giving their children complexes which a hundred years ago hadn’t even been heard of. Certainly a child needs love, and a lot of it. But the excessive permissiveness of modern parents is surely doing more harm than good.

Psychologists have succeeded in undermining parents’ confidence in their own authority. And it hasn’t taken children long to get wind of the fact. In addition to the great modern classics on child-care, there are countless articles in magazines and newspapers. With so much unsolicited advice flying about, mum and dad just don’t know what to do any more. In the end, they do nothing at all. So, from early childhood, the kids are in charge and parents’ lives are regulated according to the needs of their offspring. When the little dears develop into teenagers, they take complete control. Lax authority over the years makes adolescent rebellion against parents all the more violent. If the young people are going to have a party, for instance, parents are asked to leave the house. Their presence merely spoils the fun. What else can the poor parents do but obey

Children are hardy creatures (far hardier than the psychologists would have us believe) and most of them survive the harmful influence of extreme permissiveness which is the normal condition in the modern household. But a great many do not. The spread of juvenile delinquency in our own age is largely due to parental laxity. Mother, believing that little Johnny can look after himself, is not at home when he returns from school, so little Johnny roams the streets. The dividing-line between permissiveness and sheer negligence is very fine indeed.

The psychologists have much to answer for. They should keep their mouths shut and let parents get on with the job. And if children are knocked about a little bit in the process, it may not really matter too much. At least this will help them to develop vigorous views of their own and give them something positive to react against. Perhaps there’s some truth in the idea that children who have had a surfeit of happiness in .their childhood appear like stodgy puddings and fail .to make a success of life.

It seems that the author is most critical of()

A. social educators’ authority

B. children’ rebellion

C. psychologists’ misguidance

D. parents’ confusion