皮皮学，免费搜题
登录
搜题
【单选题】
关于光电效应有下列说法： （1）任何波长的可见光照射到任何金属表面产生光电效应； （2）若入射光的频率均大于一给定金属的红限，则该金属分别受到不同频率的光照射时，的光电子的最大初动能也不同； （3）若入射光的频率均大于一给定金属的红限，则该金属分别受到不同频率、强度相等的光照射时，单位时间的光电子数一定相等； （4）若入射光的频率均大于一给定金属的红限，则当入射光频率不变而强度增大一倍时，该金属的饱和光电流也增大一倍． 其中正确的是A.
(2) ， (4) ．
B.
(2) ， (3) ， (4) ．
C.
(1) ， (2) ， (3) ．
D.
(2) ， (3) ．
手机使用
分享
复制链接
新浪微博
分享QQ
微信扫一扫
反馈参考答案：
举一反三
【单选题】Corporate bonds are not as liquid as government bonds because ________
A.
fewer bonds for any one corporation are traded, making them more costly to sell.
B.
the corporate bond rating must be calculated each time they are traded.
C.
corporate bonds are not callable.
D.
all of the above.
E.
only A and B of the above.
【单选题】What is an advantage of investing in bonds?______.
A.
Bonds are generally of lower risk than stocks.
B.
Bonds offer a good source of income for retirees.
C.
Bonds issued by any stable country are almost risk-free securities.
D.
All of the above.
【单选题】It took me a whole hour to solve the problem.
A.
work at
B.
work on
C.
work out
D.
work over
【单选题】"Dragon" bonds are ( )
A.
dollar-denominated foreign bonds originally sold to U.S. investors.
B.
dollar-denominated bonds originally sold in Asia with non-Japanese issuers.
C.
pound sterling-denominated foreign bonds originally sold in the U.K.
D.
none of the above
【简答题】发现和简述古代器物中的人机思想萌芽案例,并简单分析原因
【简答题】周杰伦的第二张专辑名称是 。
相关题目：
参考解析：
知识点：
题目纠错 0
发布
