高考问答斗图摇骰子系列表情包:数学英语好的进！求救一道数学题！
来源：百度文库 编辑：高考问答 时间：2024/04/27 14:58:30
If two jets are flying together at an air show, each with a sound level of 120DB ,then the approximte total deciabel level is ?
A 12.3dB B 24.0dB C 123dB D 240dB
the answer is C
thanks for helping me !
please if u can , do it!
A 12.3dB B 24.0dB C 123dB D 240dB
the answer is C
thanks for helping me !
please if u can , do it!
when u have two sound sources: A and B
|A-B|=0==>3dB
|A-B|=2,3==>2dB
|A-B|=4,5,6,7,8,9==>1dB
|A-B|=10==>0dB
if their difference is over 10dB, then we take the larger one, since the smaller one cannot affect the larger one too much.
In this case, 120-120=0, so we know that the sound level will increase 3 dB, hence, we choose C.
这个应该是物理问题。
DB是声强单位，声音越强db 值越大，但并非简单的线性关系，而是对数关系。
本题根本不许精确计算，两个120DB的声音叠加，分贝数肯定>120db 而且<240db, 只有C符合要求。