问题 选择题

如图所示,直线A为电源的U—I图线,直线B为电阻R的U—I图线,用该电源和电阻组成闭合电路时,电源的输出功率和电路的总功率分别是(    )

A.4 W、8 W

B.2 W、4 W

C.4 W、6 W

D.2 W、3 W

答案

答案:C

题目分析:两图像的交点表示该电路实际工作的情况,此时干路电流是2 A,路端电压为2 V,因此电源的输出功率为4 W。由电源的U—I图线可知,电源的电动势为图象的纵坐标,电动势等于3 V,干路电流为2 A,因此电源此时的总功率为6 W,选项C正确。

单项选择题
单项选择题

Most of us would like to be both (1) and creative. Why was Thomas Edison able to invent so many things Was he simply more intelligent than most people Did he spend long hours toiling away in private Surprisingly, when Edison was a young boy, his teacher told him he was too (2) to learn anything. Other famous people whose creative genius went (3) when they were young include Walt Disney, who was fired from a newspaper job because he did not have any good ideas and Enrico Caruso, whose music teacher told him that his (4) was terrible.

Disney, Edison and Caruso were intelligent and creative men; (5) , experts on creativity believe that intelligence is not the same as creativity. Creativity is the ability to think about something in new and unusual ways, and to (6) out unique solutions to problems. When creative people are asked what enables them to solve problems in new ways, they say that the ability to find affinities between (7) unrelated elements plays a key role. They also say that they have the time and independence in a(an) (8) setting to (9) a wide range of possible solutions to a problem.

How ply is creativity (10) to intelligence (11) most creative people are quite intelligent, the (12) is not necessarily true. Many highly intelligent people (13) measured by IQ tests) are not very creative.

Some experts remain skeptical that we will ever fully understand the creative process. Others believe that a psychology of creativity is within reach. Most experts agree, (14) , that the concept of creativity as (15) bubbling up from a magical (16) is a myth. Momentary (17) of insight, (18) by images, make up a (19) part of the creative ’process. At the heart of the creative process are ability and experience that (20) an individual’s effort, often over the course of a lifetime.

Read the following text. Choose the best word(s) for each numbered blank and mark A,B,C or D on ANSWER SHEET Ⅰ.10()

A.seemingly

B.actually

C.logically

D.barely