题目

某光源能发出波长为0.61μm的可见光，用它照射某金属能发生光电效应，产生光电子的最大初动能为0.25eV．已知普朗克常量h=6.63×10﹣34J．s，光速c=3×108m/s．求：①上述可见光中每个光子的能量；②该金属的逸出功． 答案：【答案】(1)E≈2.07eV (2)W0=1.82eV【解析】①光子的能量为：．②根据光电效应方程Ekm=hv-W0得金属的逸出功为：W0=hv-EKm=2.07-0.25eV=1.82eV．Answer the questions（根据短文内容回答下列问题）I miss my familyDonnaI have a computer. My brothers and my parents have computers, too. I e-mail everyone in my family.I write one e-mail and send it to everyone. We send photographs of the children, too!CeciliaMy family is in the Philippines. My parents don’t have a telephone. I write my parents once a month. I send them many photographs. They show the letters to my brothers and sisters.GloriaI love to talk! I have a cell phone. My three sisters live in the United States, and I call them every week. My father lives in Colombia. I call him once a month. It’s very expensive.【1】What does Donna send to her brothers and parents?She sends them ______________________ and _____________________.【2】Do Donna’s parents have computers or cell phones?_________________________________________.【3】Where is Cecilia’s family?They live _________________________________.【4】How often does Gloria call her father?_________________________________________.【5】If you talk with others, which way do you like best, emails, letters or calls? Why?I like ____________________ because they are ___________________.