问题 多选题

已细氢原子的能级规律为En=

1
n2
E1(其中E1=-13.6eV,n=1,2,3,…).现用光子能量介于10eV~12.9eV’范围内的光去照射一群处于最稳定状态的氢原子,则下列说法中正确的是(  )

A.照射光中可能被吸收的光子能量有无数种

B.照射光中可能被吸收的光子能量只有3种

C.可能观测到氢原子发射不同波长的光有3种

D.可能观测到氢原子发射不同波长的光有6种

答案

根据氢原子的能级规律得E1=-13.6eV、E2=-3.4eV、E3=-1.51eV、E4=-0.85eV.最稳定的状态是基态,现用光子能量介于10eV~12.9eV范围内的光去照射基态,被吸收的光子能量有10.2eV,12.09eV,12.75,分别跃迁到n=2,3,4能级,知可能被吸收的光子能量有3种,氢原子会跃迁到第4能级,根据

C24
=6知,可能辐射6种不同波长的光.故B、D正确,A、C错误.

故选BD.

阅读理解

If you go to Juliano’s restaurant in San Francisco,you can’t get a cup of coffee or a hot cheese sandwich.All the food in the restaurant is raw,including the pizza and the rice.

Juliano thinks that cooked food makes us sick. “Food is alive,like you and me.When you cook food,you take away some of the vitamins,”he says,Juliano never eats food that is over 50 degrees.His restaurant doesn’t have a stove(火炉) or a microwave(微波炉).But he has lots of clever ideas for making raw food taste great.Instead of heat,Juliano uses water to prepare foood.He puts foods in water to make them soft.For example,he places beans in water for a few days and rice in water for two or four weeks.

Everything at the restaurant is cold,and the pizza and the rice taste good.So do the fruit and vegetable juices made from carrots ,apples,oranges and so on.Juliano’s restaurant doesn’t serve meat,but some people who cat raw food also eat raw meat.Juliano has three friends who ate raw meat.They all got very sick..One of them is still sick.

Juliano eats mostly fruits,vegetables,nuts,rice and beans.He says he feels very healthy. “Raw food gives you lots of energy,”he says,Juliano says he needs only six hours of sleep a night,and he never gets sick..

61.What is the main idea of the passage?

A.A man who eats only raw food.               B.A special restaurant in San Francisco.

C.Raw food is better than cooked food.          D.How to make raw food taste good.

62.How is the food in Juliano’s restaurant prepared?

A.Foods are put into water to make them soft.

B.Foods are cooled in a fridge.

C.Foods are heated on a stove to a certain degree.

D.Foods are boiled and then cooled.

63.What is NOT served in Juliano’s restaurant?

A.Carrot juice.         B.Cold pizza.          C.Raw rice.          D.Hot meat.

多项选择题