声强公式
声强定义为垂直于声波路径的单位面积上的声音量,用“ I”表示。标准定义是将声音能量测量为听者位置的空气中的噪声声音强度的量。声强的 SI 单位是瓦特每平方米 (W/m2)。
声强公式
声强公式可以定义为声波的功率与面积之比。
I = P/A
where,
- P = power of the sound
- A = Area
示例问题
问题1:一个人在音乐会上以2×10 -4 W 的功率欢呼。计算10m 距离处的声音强度。
解决方案:
Given,
- P (power) = 2×10-4
- A (here distance) = 10 m
So by using the sound intensity formula,
I = P / A
I = 2×10-4 / 10
I = 2×10-5
Thus the sound intensity in this condition will be 2×10-5W/m2
问题2:最后一个长凳上的一个学生距离老师20m,他以1.1×10 -4的声音强度提问。找出他以什么力量提出疑问,以至于他的老师听到了他的疑问?
解决方案:
Given,
- sound intensity (I): 1.1×10-4
- Distance (A) : 20m
So by rearranging the formula for sound intensity,
P = I × A
and substituting the values of I and A,
P = 1.1 ×10-4×20
P = 2.2×10-3
Thus he has asked the doubt at a power of 2.2×10-3W
问题3:功率为8×10 -4的救护车在30m距离处的警笛强度是多少?
解决方案:
Given,
- power (P) = 8×10-4
- Distance (A) = 30m
So, according to the sound intensity formula,
I = P / A
I = 8×10-4×30
I = 0.024
Thus the sound intensity in this condition will be 0.024 W/m2
问题4:如果一个朋友以5×10 -4的声功率和10×10 -4的声强呼叫他,两个朋友之间的距离是多少?
解决方案:
Given,
- Power (P) = 5×10-4
- Sound intensity (I) = 10×10-4
So by rearranging the formula for sound intensity,
A = P / I
and substituting the values of I and P,
A = 5×10-4 / 10×10-4
A = 0.5m
Thus the distance between them is 0.5m.
问题5:歌手以6×10 -4 的功率唱歌相对于距离3m的人的声音强度是多少。
解决方案:
Given,
- Power (P) = 6×10-4
- Distance (A) = 3×10-4
So, according to the sound intensity formula,
I = P / A
I = 6×10-4 / 3
I = 2×10-4
Thus the sound intensity in this condition will be 2×10-4 W/m2