在双缝干涉实验中，以下说法正确的是：
A．两狭缝到屏上距离等于半个波长的点将出现亮纹
B．两狭缝到屏上距离相等的点将出现暗纹
C．用红光做实验时干涉条纹比用蓝光时大
D．用紫光做实验时干涉条纹比用绿光时大
答案：C
题目分析：两狭缝到屏上距离等于半个波长的点将出现暗纹，选项A错误；两狭缝到屏上距离相等的点将出现亮纹，选项B错误；由公式
可知红光波长较长，干涉条纹比用蓝光时大，选项C正确；同理选项D错误；故选C
点评：本题难度较小，熟记并理解公式每个字母的物理意义
| Questions 14 to 16 are based on a news report about retirement. You now have 15 seconds to read questions 14 to 16. |
According to the news reports, what happened at the Providence Retirement Home in New Albany last year
A．Two deer running in the hall.
B．Maggots in a resident’s leg wound.
C．A fire breaking out.
D．An investigation of 1400 vet facilities.