题目

如图所示是氢原子的能级图，现有大量处于n=4激发态的氢原子向低能级跃迁，所辐射的光子中，只有一种能使某金属产生光电效应。以下判断不正确的是（ ）A.这些氢原子最多可辐射6种不同频率的光子B.这些氢原子辐射出光子后核外电子的动能将减小C.若氢原子从激发态n＝5跃迁到基态，辐射出的光子一定能使该金属产生光电效应D.若氢原子从激发态n＝4跃迁到n＝3，辐射出的光子一定不能使该金属产生光电效应根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。Some experts feel that cars are certain to fall into disuse. They see a day in the not-too-distant future when all cars will be deserted and made useless. 1. They hold that the car will remain a leading means of city travel in the foreseeable future. The car will undoubtedly change greatly over the next 30 years. It should become smaller, safer, and more practical, and should not be powered by the gas engine. 2. Unless changes take place in the power system, the car in the future will still be the main problem in city traffic jams. 3. When the car enters the highway system, a small arm will drop from the car and connect with a rail, which is similar to hose(软管) powering subway trains electrically. Once joined to the rail, the car will become electrically powered from the system and control of the car will pass to a central computer. 4. The driver will use the telephone to dial instructions about his position and the place he heads for into the system. The computer will find the best way and reserve space for the car all the way to the correct exit from the highway. ____5. It is believed that an automated highway will be able to deal with 10,000 cars per hour, compared with the 1,500 to 2,000 cars that can be carried by a present-day highway.A. The driver will be free to relax and wait for the call that will warm him of his coming exit.B. Other experts however think the car is here to stay.C. The car of the future should be far more pollution-free than present types.D. There will be plenty of policemen on the highway to control the traffic.E. One suggested solution to this essential problem is the automated (自动的) system which seems to hold water.F. The computer will then monitor all the car’s movements.G. All of the experts don’t know what will happen in the future.