试题与答案

如一声压级为70dB，另一声压级也为70dB，则总声压级为( )。A．(A) 70

来源：www.tikuol.com
题型：单项选择题

题目：

如一声压级为70dB，另一声压级也为70dB，则总声压级为( )。

A．(A) 70dB

B．(B) 73dB

C．(C) 90dB

D．(D) 120dB

答案：

参考答案：B

解析：
[解题思路] 两个以上独立生源作用于某一点，产生噪音的叠加。总声功率和总声强可以线性叠加。但总声压不能直接叠加。由于总声压计算需要查表，故本题选择一个特例即两个声源的声压级相等。
[解题关键] 当两个声压级相等时，总声压级：LP=LP1+lg2≈LP1+3(dB)。

考点：注册环保师环保专业基础环境监测与分析
试题推荐
题型：填空题
用方框中所给词语的适当形式填空，每个词语只能使用一次。
get,   go,   be,   swim,   learn,   game,   different,   good,   stop,   leave
1. Jim ________ his math homework at home yesterday.
2. _______ is my hobby.
3. Excuse me, have you ________ any books about biology?
4. What's the ________ between American English and British English?
5. Where's Jim? He has ________ to plant trees with his classmates.
6. Tom thinks that the movie Hero is much ________ than Crouching Tiger, Hidden Dragon (卧虎藏龙).
7. The students ________ talking when the teacher came in.
8. The Olympic ________ of 2008 will be held in Beijing.
9. I've _______ in this city for about 30 years.
10. There are a lot of people ________ English in China now.
查看答案
微信公众账号搜索答案