【选修3-5选做题】
已知金属铯的逸出功为1.9 eV,在光电效应实验中,要使铯表面发出光电子的最大初动能为1.0 eV,入射光的波长应为____m。
4.3×10-7
建筑物基础埋深指的是()。
A.从±0.00到基础底面的垂直距离
B.从室外地面到基础底面垂直距离
C.从室外设计地面到垫层底面的垂直距离
D.从室外设计地面到基础底面的垂直距离
Questions 19 to 22 are based on the conversation you have just heard.
A.It’s crowded with people.
B.It’s full of computers.
C.Lunch is being served there.
D.Only few people in there.