问题 实验题

某高三年级的一同学在科技创新大赛中根据所学物理知识设计了一种“闯红灯违规证据模拟记录器”,如图甲所示,它可以通过拍摄照片来记录机动车辆闯红灯时的情景。它的工作原理是:当光控开关接收到某种颜色的光时,开关自动闭合,且当压敏电阻受到车的压力,压敏电阻的阻值随压力变化的图像如图乙所示,它的阻值变化引起电流变化,达到一定值时,继电器的衔铁就被吸下,工作电路中的电控照相机就工作,拍摄违规车辆。光控开关未受到该种光照射就自动断开,衔铁不被吸引,工作电路中的指示灯发光。  

(1)要记录违规闯红灯的情景,光控开关应在接收到__________光(填“红”“绿”或“黄”)时自动闭合;

(2)已知控制电路电源电动势为6V,内阻为1 Ω,继电器电阻为9 Ω,当控制电路中电流大于0.06 A时,衔铁会被吸引。则只有质量超过__________kg的车辆违规时才会被记录。(重力加速度取10 m/s2

答案

(1)红

(2)400

单项选择题
单项选择题

The conception of God and nature and of the relation of man to both provided the 18th- century philosophers with their faith in the worth and dignity of the individual man and the efficacy of human reason. The 18th century was the moment in history when men experienced the first flush and freshness of the idea that man is master of his own fate; the moment in history, also, when this emancipating idea, not yet brought to the harsh test of experience, could be accepted with unclouded optimism.
Never had the nature seemed less mysterious, more simply constructed, more open and visible and eager to yield its secrets to common-sense questions. Never had the nature of man seemed less perverse, or the intelligence and will of men more pliable (yielding) to rational persuasion. Never had social and political evils seemed so wholly the result of ignorance and superstition, or so easily corrected by the spread of knowledge and the construction of social institutions on a rational plan.
The first task of political science was to discover the natural rights of man, the second to devise the form of government best suited to secure them. And for accomplishing this high task, for creating and maintaining a society founded on justice and equality, the essential freedom was freedom of the mind.

In the paragraphs that come before the first reproduced here, the author discusses most probably ______ .

A.the background of God coming to the earth

B.an account of nature appearing on the earth

C.what the 18th-century philosophers found

D.the relations between the 17th-century people and God